Examples of the applications of magnetic materials include:
- magnetic cores for use in transformers
- permanent magnets which drive electric motors
- computer data storage
- spintronics
- high-speed read/write heads in disk memory devices
- magnetic stripes on credit cards for personal data
- dipole magnets for beam handling in particle accelerators
Advances in materials, along with improved integrated circuits, have resulted in modern portable products, such as camcorders and notebook computers. Many experts believe that for research in magnetic materials, 'the future lies in films'.
An enormous worldwide industry has grown from magnetic film research and applications. Most of the activity is in information storage, with emerging needs in optical communications, integrated microwave circuits and nonvolatile computer memory. For recording applications, magnetic thin films are preferred to bulk materials for two reasons.
Firstly, they can be mass processed easily, and secondly, their composition and properties can be easily controlled and optimised for particular applications. A new field of artificially ordered magnetic thin film structures has been created. These magnetic multilayers or superlattices have interesting physical properties and the potential for producing technological advances in new magnet synthesis and information storage and retrieval.
In 2002 IBM scientists announced they could compress an enormous amount of data onto a small area (1.5 GBit/mm2). This was achieved via spintronics' (magnetoelectronics), a novel technology that uses the quantum spin states of electrons alongside the charge state. New challenges like achieving practical spintronics in semiconductors would allow for many novel devices to be produced.
A user searching for "spintronics" articles would find that the magnetoelectronics control term, introduced in January 2003 is used for spintronics and magnetoelectronic devices. It has the following related terms and classifications:
Related Terms: electron spin polarisation; giant magnetoresistance; magnetic logic; magnetic sensors; magnetic storage; magnetic tunnelling; magnetoresistive devices; spin Hall effect; spin polarised transport; spin valves
Classifications
- A7225: Spin Polarized transport
- A7500: Magnetic properties and materials
- A7570: Magnetic films and multilayers
- B3100: Magnetic materials and devices
- B3120J: Magneto-acoustic, magnetoresistive, magnetostrictive and magnetostatic wave devices
Inspec provides coverage of magnetic materials, their preparation, physical properties and applications.
Section A
In Section A (Physics Abstracts), the following parts of the Classification Scheme contain relevant information:
A75... Magnetic properties and materials
Theory
The A7510 section covers the following topics
- A7510D: Crystal field theory and spin Hamiltonians
- A7510H: Ising and other classical spin models
- A7510J: Heisenberg and other quantised localised spin models
- A7510L: Band and itinerant models
- A7510N: Spin-glass models
Properties
Intrinsic properties of magnetic materials are classified under the A7530 section.
- A7530C: Magnetic moments and susceptibility in magnetically ordered materials
- A7530D: Spin waves in magnetically ordered materials
- A7530E: Exchange and superexchange interactions in magnetically ordered materials
- A7530F: Spin-density waves in magnetically ordered materials
- A7530G: Magnetic anisotropy
- A7530H: Magnetic impurity interactions
- A7530K: Magnetic phase boundaries
- A7530M: Valence fluctuations, Kondo lattice and heavy fermions in magnetically ordered materials
- A7530S: Magnetocaloric effect in magnetically ordered materials
- A7530T: Surface magnetism
- A7530V: Enhanced magnetoresistance in bulk magnetic materials
Materials
When searching for particular materials Inspec provides the user with an extensive range of options.
Papers dealing with films and multilayers are classified under: A7570: Magnetic films and multilayers.
Information on magnetic superlattices and multilayers can also be found under: A7550R: Magnetism in interface structures and A7570C: Interfacial magnetic properties.
Magnetic fluids and ferrofluids are an important class of materials with applications in biology and medicine and as pressure sensors and seals. They are classified in:
- A7560J: Fine-particle systems
- A7550M: Magnetic liquids
- A8270D: Colloids
Papers on the magnetic properties of permanent magnet materials are classified under: A7550V: High coercivity materials.
Magnetic and dilute magnetic semiconductors gain further importance for their application in future spintronic devices, they are classified under A7550P: Magnetic semiconductors.
Nanostructured and amorphous magnetic materials are covered in A7550K and A7570B: Magnetic properties of nanostructures: Amorphous and nanostructured magnetic materials.
Magnetic recording materials are classified in A7550S: Magnetic recording materials
Molecular magnets such as Mn12-acetate are classified in A7550X: Molecular magnets.
Diamagnetic and paramagnetic materials are classified under A7520.
Effects
Inspec also covers a wide range of magnetic effects and related topics.
- A6780J: Magnetic properties, and diffusion (solid helium/quantum crystals)
- A7215G: Galvanomagnetics and other magnetotransport effects (metals/alloys)
- A7215H: Thermomagnetic effects (metals/alloys)
- A7220M: Galvanomagnetics and other magnetotransport effects (semiconductors/insulators)
- A7220N: Thermomagnetic effects (semiconductors/insulators)
- A7255: Magnetoacoustic effects (electronic transport)
- A7225: Spin polarised transport
- A7340H: Quantum Hall effect
- A7470H: Magnetic superconductors
- A7430C: Magnetic properties of superconductors
- A7820L: Magneto-optical effects (condensed matter)
Section B
In Section B (Electrical & Electronics Abstracts), the most relevant chapters of the classification scheme are:
- B3110: Magnetic materials
- B3110C: Ferromagnetic materials (magnetic properties of permanent magnet materials are classified here)
- B3110E: Ferrites and garnets. Garnets are important materials for applications, including thin film devices and bubble domain devices. Yttrium iron garnet (YIG) in particular has become indispensable in microwave technology.
- B3120: Magnetic material applications and devices
- B3120B: Magnetic recording. Magneto-optic recording can be found under this classification and also under:
- B4160: Magneto-optical devices (papers on magnetic tapes, discs and recording heads are classified here, along with papers on particulate and thin film recording media)
- B3120D: Magnetic cores
- B3120E: Permanent magnets
- B3120G: Microwave devices
- B3120J: Magneto-acoustic, magnetoresistive, magnetostrictive and magnetostatic wave devices
- B3120L: Magnetic bubble domain devices
- B3120N: Magnetic thin film devices
- B3120W: Other magnetic material applications and devices
- B3240E: Superconducting coils and magnets
- B5120: Magnetostatics
- B5130: Magnetic effects of electric currents
- B5180F: Solenoids and electromagnets
There are many controlled index terms in the area of magnetism and magnetic materials, some of the most important terms for the topics discussed in this article are:
- ferrimagnetic properties of substances
- ferrite applications
- ferrite devices
- ferrites
- ferromagnetic properties of substances
- garnets
- magnetic bubble devices
- magnetic cores
- magnetic epitaxial layers
- magnetic fluids
- magnetic multilayers
- magnetic properties of amorphous substances
- magnetic properties of fine particles
- magnetic recording
- magnetic thin film devices
- magnetic thin films
- magneto-optical recording
- magnetoresistive devices
- magnetostatic wave devices
- magnetostrictive devices
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