Magnets or magnetic bodies characterised by the magnetic materials therefor. Selection of materials for their magnetic properties (H01F 1/00).

Thin magnetic films (H01F 10/00).

Permanent magnets (H01F 7/00).

Electromagnets (H01F 7/00) including, for example, superconductive magnets (H01F 6/00); details thereof such as coils (H01F 5/00), cores, yokes, and armatures (H01F 3/00).

Fixed and variable transformers including, for example, superconductive or cryogenic transformers; adaptations thereof for specific applications or functions; details thereof (H01F 19/00, H01F 21/00, H01F 27/00, H01F 29/00, H01F 30/00, H01F 36/00, H01F 38/00).

Fixed and variable inductances; adaptations thereof for specific applications or functions; details thereof (H01F 17/00, H01F 21/00, H01F 27/00, H01F 29/00, H01F 37/00, H01F 38/00).

Apparatus or processes for magnetising or demagnetising (H01F 13/00).

Apparatus or processes specially adapted for manufacturing or assembling devices covered by this subclass (H01F 41/00).

Further information:

Groups H01F 17/00 - H01F 38/00 (with the exception of groups H01F 27/42 and H01F 38/32) cover only structural or constructional aspects of transformers, inductive reactors, chokes or the like. These groups do not cover circuit arrangement of such devices, which are covered by the appropriate functional places.

Classification proceeds by assigning the most restricted possible CPC symbol to the document, followed by additional knowledge tagging using Indexing Code symbols. This implies that CPC head subgroups (corresponding to IPC subgroups) should only be used if no other possibility could be found for classifying the document in a more restricted subgroup.

If the set of claims comprises product or article and method claims an CPC symbol should be assigned to each of these categories. However if the most suitable subgroup for a claim of a given category, e.g. product, does not exist in the main group of the same category, e.g. product group, and can only be found in groups of another corresponding category, e.g. a group for a method to manufacture the product, this latter subgroup should be assigned to the claim e.g. method subgroup assigned to a product claim. For example a document with no method claims dealing with a magnetic tunnel junction in which the spacer has been processed in such a way that its material structure becomes inventive, would still be given the method CPC symbol H01F 41/307 as product CPC symbol H01F 10/3254 is silent over any material inventive features.

Another use of Indexing Codes can be made for particular cases where the invention is a specific property of a given type of material or article and this property is classified only in subgroups of another specific material type. In this case the corresponding CPC symbol cannot be given. Consequently the Indexing Code should be given together with an CPC symbol corresponding to the material described in the document. For example: a sintered nanocomposite exchange spring magnet of SmCo/Fe cannot be given H01F 1/0579 as CPC symbol since the latter symbol belongs to NdFeB magnets classification subtree. Therefore the combination H01F 1/0557 and H01F 1/0579 should be used.

Bulk magnetic materials: antiferromagnetic, diamagnetic, paramagnetic, hard and soft ferromagnetic materials.

0D, 1D and 2D magnetic (nano)structures.

Materials cover metallic materials, compounds (i.e. mainly non-metallic materials) or organic materials. Selected types of magnetic materials are highlighted within specific subgroups.

H01F 1/00 is mainly concerned with bulk materials except for some specific subgroups.

H01F 1/0009 covers antiferromagnetic bulk material.

H01F 1/0018 covers diamagnetic or paramagnetic bulk material.

H01F 1/0027 covers thick magnetic films formed with methods classified under H01F 41/16.

Treatment of the materials, e.g. compacting, sintering, bonding are also classified into this group.

Thick magnetic films characterized by being manufactured with methods associated under H01F 41/16. This subgroup encompasses single layers and multiple layers of thick films. This subgroup primarily includes soft magnetic thick films but also includes hard magnetic thick films meeting the above requirements.

Thick magnetic films can be distinguished from thin magnetic films by assessing their respective manufacturing methods:

Thick magnetic films are typically obtained from magnetic particles and bonding agent, according to manufacturing methods of groups H01F 41/16 thereby forming a composite film.

Thin magnetic films are typically obtained by deposition or plating of magnetic material, according to manufacturing methods of groups H01F 41/18-H01F 41/34.

Hard magnetic thick films applied in magnetic record carriers are classified under G11B 5/70.

Hard magnetic thick films forming permanent magnets are classified according to the composition of the magnetic particles; i.e. under H01F 1/047 and its subgroups, primarily under H01F 1/0533, H01F 1/0558 or H01F 1/0578. When the composition of the magnetic particles is nominal, i.e. not a restriction, classification will usually fall under H01F 1/08 and its subgroups, i.e. H01F 1/083.

These subgroups cover:

0D, 1D and 2D magnetic (nano)structures wherein the size and carriers confinement alters the magnetic properties. Embedded magnetic nanostructures.

1. Nanoparticles used in bioscreening (diagnostic, separation) are classified in these subgroups irrelevant of their composition and size effect.

2. If a strong effect of the size of the nanoparticles belonging to the groups cited in the above table is shown on the magnetic properties, then it is also classified in H01F 1/0036-H01F 1/0063

Magnetocaloric materials. Subdivided in metallic or compounds materials.

Materials with specific coercivity; Laves phases or magnetic shape memory materials. Mainly those latter examples are classified in these subgroups.

Hard magnetic metals or alloys characterised by composition, by shape and by the process or treatments to obtain articles including these materials.

Subgroup H01F 1/0579 is concerned with nanocomposite exchange spring magnets.

H01F 1/057 covers so-called R-T-B magnets (Nd₂Fe₁₄B phase).

H01F 1/059 covers magnets with a Sm₂Fe₁₇N₂ phase.

Magnets obtained from the corresponding materials are classified in the same subgroups according to method criteria (process or treatments undergone by the material forming the magnet) on which part of the classification refinement is based.

Hard magnetic metallic particles characterised by shape and by treatments to obtain articles including these materials.

The subgroups are generally concerned with particles used in magnetic recording or under subgroup H01F 1/08 metallic particles for permanent magnets when composition is not specifically mentioned in the claims.

Hard magnetic non-metallic particles characterised by shape and by treatments to obtain articles including these materials.

H01F 1/09 can cover hard metallic particles covered with an oxide layer

For rare earth containing particles covered with an oxide layer, subgroups H01F 1/0552 and H01F 1/0572 would take precedence except if the oxide layer is the core of the invention.

Hard non-metallic magnets such as Ba-ferrite type of magnets

Soft magnetic metals or alloys characterised by composition, by shape and treatments to obtain articles including these materials.

Fe-Ni and Fe-Si alloys and their shape are classified in the subgroups H01F 1/14708-H01F 1/14791.

Other compositions than Fe-Ni, Fe-Si must be classified according to a shape criterion: subgroups H01F 1/16 and onwards for sheets, H01F 1/20 and onwards for particles and H01F 1/143 for wires or for no specific shape given: subgroup H01F 1/147. If no specific shape or composition criterion is given, the H01F 1/14 symbol should be given.

Soft magnetic amorphous metals, also including nanocrystallites, characterised by composition and by methods to obtain articles including these materials.

The method section of these subgroups has to be used in combination with the method subgroups H01F 41/0206-H01F 41/0246.

Soft magnetic sheet of metals or alloys.

H01F 1/18 covers insulated sheets

Soft magnetic particles of metals or alloys characterised by shape and by treatments or methods to obtain articles including these materials.

H01F 1/20 covers particles

H01F 1/22 covers compacted particles.

H01F 1/24 covers insulated compacted particles.

H01F 1/26 covers compacted particles wherein insulator are organic macromolecules.

Subgroup H01F 1/28 concerns non compacted bodies.

Soft magnetic particles compacted in a bonded body (magnetic core or noise suppressing sheet) are classified in H01F 1/26 in combination with H01F 41/0246 for magnetic cores only.

Soft metallic particles covered with an oxide layer.

Soft non-metallic materials characterised by composition, by shape and treatments to obtain articles including these materials.

H01F 1/34 covers bulk non metallic material such as ferrite.

H01F 1/36 covers non-metallic particles.

Subgroup H01F 1/24 would take precedence in the case of oxide insulated particles being part of a compacted body.

Magnetic semiconductors and half-metals (Heusler).

Perovskites (H01F 1/407) and half-metals (H01F 1/408) are classified under the arborescence of magnetic semiconductors even if they might not be necessarily a semiconducting material.

Organic or organo-metallic materials.

Magnetic and magnetorheologic fluids.

Cores, yokes and armatures which are single parts or arrangements of several parts of ferromagnetic material used to guide magnetic flux.

Further information:

Printed coils.

Wound electric conductors.

Further information:

Superconducting magnets and coils and accessories necessary to operate them.

Further information:

Magnets in general.

Further information:

Although magnets are normally classified in the respective subgroups of an application when provided for, the presence of features for which an appropriate subgroup does not exist in the application main group but in H01F 7/00, requires the respective subgroup in H01F 7/00 to be allocated.

For example, an electromagnetically actuated valve which is normally classified in F16K 31/06, should also be classified in H01F 7/10 for details concerning the use of alternating current for powering the actuator.

Hard and soft ferromagnetic thin films. Antiferromagnetic thin films. Single layers and (spin-exchanged coupled) multilayers are both considered as thin films.

Thin film materials cover metallic materials, compounds or organic materials.

H01F 10/00 is concerned with ferromagnetic or antiferromagnetic materials in the form of thin films.

A thin film is generally less than a couple of microns thick and can be defined as being manufactured by the methods classified in subgroups H01F 41/18-H01F 41/34.

H01F 10/002 covers antiferromagnetic, single layer, thin films.

H01F 10/005 covers organic or organo-metallic thin films. Graphene thin films are also given this symbol in case magnetic properties are claimed.

H01F 10/007 covers granular thin films.

Thin films characterised by contact with conductors.

Single layer thin films characterised by properties or composition.

Metallic single layer thin films characterised by their composition, e.g. amorphous, crystalline.

Compounds single layer thin films characterised by their composition. Further divided in amorphous, magnetic semiconductors, half-metals (Heusler), perovskites and ferrites.

Multilayers characterised by intermediate layers.

H01F 10/30 covers specific seed, template and cap layers.

Spin-exchanged-coupled multilayers characterised by the interaction between the different layers and refined by composition of the single interacting layers.

Multilayers with perpendicular magnetic anisotropy of the type of (Co/Pt)n are also classified in H01F 10/3236 but H01F 10/3286 takes precedence.

Spin-exchanged-coupled multilayers characterised by having a thin non-magnetic spacer between magnetic layers.

Typical TMR and GMR structures.

Tunnel magnetic junctions (a tunnel barrier sandwiched between two magnetic layers) are classified in H01F 10/3254.

However TMR junctions with additional pinning of one of the magnetic layers (by an AF layer or a SAF/AAF multilayer) do not have a subgroup of H01F 10/3254 where they can be classified. Therefore an Indexing Code of H01F 10/3268-H01F 10/3281 is generally additionally given.

Spin valves (GMR structures) with no specificity of the magnetic layers are generally classified under H01F 10/325.

If no subgroup in H01F 10/00 can reflect the invention of a product claim for a spin-exchanged-coupled multilayer, subgroup from the corresponding method subgroups H01F 41/302-H01F 41/309 is assigned when appropriate.

Apparatus or processes for magnetising permanent magnets or for demagnetising magnetic bodies.

Inductances of fixed value not used /useable for high power.

Further information:

"Signal type" means that these inductances are not used/useable for high power.

Transformers or coupled inductances.

Further information:

"Signal type" means that these transformers or inductances are not used/useable for high power.

The subgroups basically define different frequency ranges.

Transformers or inductances which are variable and not used/useable for high power.

Further information:

Constructional features of transformers or inductances in general.

Further information:

In this group no distinction is made between "signal type" and "power type" applications except for the cases mentioned below. "Power type" means that these transformers or inductances are used/useable for high power.

H01F 27/00 covers constructional features of transformers and inductances falling under the titles of H01F 17/00 - H01F 21/00 and H01F 29/00 - H01F 38/00. If a subgroup for a specific detail exists under H01F 17/00 - H01F 21/00 and H01F 29/00 - H01F 38/00, this subgroup takes precedence over H01F 27/00.

H01F 27/00 also covers details of cores, coils and magnetising arrangements in H01F 3/00 - H01F 7/00 and H01F 13/00 if there is no appropriate subgroup for the respective constructional features in the H01F 3/00 - H01F 7/00 and H01F 13/00.

Variable transformers or inductances of the "power type", i.e. used/useable for high power.

Fixed transformers of the "power type", i.e. used/useable for high power.

Further information:

Transformers with superconducting windings.

Transformers with windings operating at cryogenic temperature.

Fixed inductances of "power type", i.e. used/useable for high power.

Transformers or inductances for specific applications or functions.

Welding transformers and discharge lamp ballasts are covered by H01F 38/08

even if they do not explicitly have a high leakage (i.e. gap in magnetic flux path).

Apparatus or processes for manufacturing or assembling transformers, inductances, reactors or choke coils.

Apparatus or processes for manufacturing or assembling magnetic circuits, permanent magnets or coils.

Apparatus or processes for applying magnetic films to substrates and forming magnetic nanostructures.

Methods for encapsulating/impregnating. Refers to cases where a whole device (e.g. coil and core of a transformer or a choke) is encapsulated.

Encapsulation only of a winding is to be classified in H01F 41/127.

Manufacturing of hard or soft magnetic articles. Manufacturing of coils.

Methods and apparatus for manufacturing soft magnetic articles characterised by the shape of the magnetic material composing those articles. H01F 41/14 takes precedence.

Methods and apparatus for manufacturing permanent magnets characterised by process steps performed on the magnetic material or on the magnets.

Methods and apparatus for manufacturing coils.

Further information:

The most important subgroups are related to:

Processes or apparatus for manufacturing coils by winding.

Processes or apparatus for winding flat conductive wires or sheets with insulation.

To be classified here, the conductive wires or sheets and the insulation must initially be separate, and must be wound simultaneously.

The figure below is an example of material classified in this subgroup. In the figure, the conductive sheet 40 and the insulating sheet 52 are wound simultaneously to form an insulated coil.

Processes or apparatus for winding non-flat conductive wires with insulation.

To be classified here, the conductive wires or sheets and the insulation must initially be separate and must be wound simultaneously.

The figure below is an example of material classified in this subgroup. In the figure, for example, the conductive wire 24 and the insulation tapes 21 and 22 are wound simultaneously to form an insulated coil.

Processes or apparatus for forming taps or terminals while, or in conjunction with winding.

The figure below is an example of material classified in this subgroup. In the figure, the first terminal 3 is wrapped, then the first section 9 of the bobbin 1 is wound. The wire is then wrapped around the second terminal 5. The terminal connections are thus formed in conjunction with the winding of the bobbin.

Processes or apparatus for deforming the cross section or shape of the winding material in conjunction with winding.

The figure below is an example of material classified in this subgroup. In the figure, the circular material wire 50 is transformed into the deformed rectangular wire 52 just before winding.

Processes or apparatus for winding coils while measuring electrical characteristics, e.g. resistance, inductance or capacitance.

The figure below is an example of material classified in this subgroup. In the figure, the existence of an electrical short circuit is detected by measuring voltage during winding.

Thin films deposition methods not provided in subgroups below.

Deposition methods and apparatus for forming thick magnetic films, usually performed by macroscopic methods.

The obtained material is a thick magnetic film or any precursor of thick magnetic film, generally in the form of magnetisable pastes, inks or glass frits.

Deposition methods and apparatus for forming thin magnetic films characterised by deposition methods.

Deposition from liquids.

H01F 1/26 covers deposition from liquids using electric currents.

H01F 1/28 covers deposition from liquids by liquid phase epitaxy.

Deposition methods and apparatus for forming multilayered nanostructures, especially spin-exchange-coupled multilayers corresponding to product subgroups H01F 10/324-H01F 10/3295, characterised by specific process steps leading to a specific change of properties of the grown superlattice (H01F 41/303-H01F 41/304) or to a given structure (H01F 41/305-H01F 41/309).

Deposition methods and apparatus for applying a single layer on a magnetic thin film characterised by specific process steps.

H01F 41/34 covers deposition in patterns (i.e. using lithography).

Spin filters capping layers for TMR/GMR structures (products) are also classified within method subgroup H01F 41/325.