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The magnetic properties of nanocrystalline cobalt ferrite could be tuned with substituting small amount of non-magnetic rare earth cation at Fe site in cobalt ferrite. The variation in magnetic parameter of samples could also be obtained by measuring its anhysteretic magnetization curve without tailoring its chemical composition. The magnetic parameters such as coercivity, remanent magnetization and saturation magnetization critically depend upon different values of external magnetic fields. In the present study, the anhysteretic magnetization curve of the samples CoFe2−xLaxO4 (x=0.025, 0.05, 0.075 and 0.1) has been recorded and response of coercivity to different maximum values of applied field has been investigated. It has been observed that the response of coercivity to different maximum values of applied field shows non-linear behavior. The analysis of the response of coercivity to different values of applied field in low field regime has been carried out with the help of Rayleigh laws. The analysis of the plot yields significant information about magnetic anisotropy.

In the present study, the effects of B2O3 addition on the remanence properties of barium ferrite magnets are examined. The relationship between isothermal magnetization remanence M-R(H) and demagnetization remanence M-D(H) for non-interacting single domain particles, M-D(H)=M-R(H-max)-2M(R)(H), was used in order to investigate the interactions between particles. We have found that remanence magnetization M-R increased by 40% in magnitude with B2O3 addition in addition to the weakened couplings between particles. The B2O3 addition seems to supply the required conditions for usage of these materials in the magnetic recording media. (C) 2012 Elsevier B.V. All rights reserved.

Magnetic hysteresis curves were calculated using the Monte Carlo method to study the dependence of magnetic properties on the distribution of local magnetic sites on the grain boundaries of sensitized Alloy 600. The simulated curves illustrate that the total number of the magnetic sites and the standard deviation of the site distribution on grain boundary influence strongly the magnetic remanence and coercivity. The magnetic system can, therefore, be regarded as a magnetic granular structure with a distribution, and the results suggest a possibility of new method to control magnetic hysteresis.

The analytical way to describe uniaxial single-domain particles, using new symmetry considerations on the magnetic anisotropy, as a vector hysteresis unit (vector hysteron), is presented. The main characteristics of the vector hysteron such as the longitudinal hysteresis loops, transversal hysteresis loops and rotational hysteresis loops are presented. An extension of the vector hysteron and a vector hysteron that can be applied to the ferroelectric hysteresis are also presented.

The physics of magnetic state change in single domain magnetic grains (called Stoner particles) is interesting from the fundamental as well as the applied points of view. A change in magnetization can be finely tuned with a specific time variation of an externally applied magnetic field. It may also occur naturally (without application of a field) at very low temperature with quantum tunneling and at higher temperature with thermal excitation. The optimal (usually shortest) time altering the magnetization along with the smallest applied magnetic field are sought in technological applications such as high-density reading or writing of information, spintronics, quantum information and quantum communication systems. This work reviews the magnetization change with a time dependent field and temperature and discusses the time it takes to alter the magnetization as a function of the control parameter chosen, temperature and material parameters.

Recent advances in high-density magnetic storage and spin electronics are based on the combined use of novel magnetic materials with conventional microelectronic materials (metals, insulators and semiconductors). A bit is stored as a magnetization state in some ferromagnetic material (FM) and controlled with an external field to alter the magnetization state. As device size is shrinking steadily toward the nanometer and the need to increase the processing bandwidth prevails, racing toward higher frequencies is getting even more challenging. In magnetic systems, denser storage leads to finer magnetic grains and smaller size leads to single magnetic domain physics. The Stoner–Wohlfarth (SW) model is the simplest model that describes adequately the physics of fine magnetic grains containing single domains and where magnetization state changes by rotation or switching (abrupt reversal). The SW model is reviewed and discussed with its consequences and potential applications in the physics of magnetism and spin electronics.

In this paper, a theoretical model has been established to study the contributions of the magnetization rotations to the magnetic properties of stressed amorphous magnetic films. The influences of both magnitude and direction of the applied stress on the magnetic properties have been discussed. The results show that the shapes of the hysteresis loops are significantly dependent on the applied stress. For amorphous magnetic film with positive magnetostriction, the longitudinal tensile stress can increase the coercivity but the remanence seems independent on the stress. Both the coercivity and remanence approach zero while the longitudinal compressive stress is large enough. The observed magnetostrictions of the amorphous magnetic films are influenced markedly by applied stress.

The magnetic properties of a single crystal of SmNiSn with the orthorhombic e-TiNiSi-type crystal structure have been investigated by magnetic susceptibility, magnetization and electrical resistivity measurements from 1.5 K to room temperature. Two anomalies have been found in the magnetic susceptibility, indicating an antiferromagnetic phase transition at T N =9.4 K and a second transition at 4.4 K. A large magnetic anisotropy has been found at low temperatures in the temperature and field dependencies of magnetic susceptibility and magnetization. Below 80 K, the easy axis of the magnetization is the c-axis. At T=2.0 K , the c-axis magnetization curve exhibits metamagnetic-like behavior at Hc=42 kOe and reaches 0.54 emu/g at H=55 kOe, whereas for the a- and b-axis the magnetization is linear and smaller. The paramagnetic susceptibilities do not follow the Curie–Weiss law suggesting a large van Vleck contribution of the Sm ions.

A sample extraction system was attached to an induction magnetometer which conventionally had been used for measuring the magnetization in pulsed magnetic fields. It became possible to measure the magnetization directly in materials with a remanence such as permanent magnets. The second derivative of magnetization was also deduced to determine the anisotropy field.