We evaluate the energy barrier distributions of coupled Co particles as a function of their concentration, which changes the strength of magnetostatic interactions, in a multidimensional space to take into account possible collective reversal. The distributions are evaluated at the remanence, demagnetized state and coercivity for Co particles with 2D random anisotropy easy axes orientations and...

The Sm-content dependence of phase composition, anisotropy, and other magnetic properties of Sm1+δCo5 (δ ≤ 0.12) ribbons melt spun at 10 m/s has been studied. The samples consist of hexagonal SmCo5 grains whose c axes are preferentially aligned along the long direction of the ribbon. The lattice parameter a and the cell volume (V) increase with increasing Sm content δ, whereas c decreases. Sm a...

Magnetic immunoassays utilizing magnetic marker and high Tc superconducting quantum interference device (SQUID) have been performed. In this magnetic method, binding-reaction between an antigen and its antibody is detected by measuring the magnetic field from the magnetic marker. First, we discuss the magnetic property of the marker, and show that Fe3O4 particles with diameter of 25 nm can be u...

A numerical model based upon the "Stoner-Wohlfarth theory" has been developed to predict Isothermal Remanent Magnetisation (IRM) curves for a system of fine particles with uniaxial anisotropy. This paper reports the predictions of our model for the effects of easy axes alignment on the IRM curve. We have also investigated the effect of the standard deviation after the application of a non-satur...

In the usual thin film magnetic memory, that which utilizes the two stable easy direction magnetization states for storage, inverted films ( H , > H r ) are often used to reduce disturb sensitivity. In general, inverted films exhibit a high angular dispersion and an open hard direction hysteresis loop with considerable remanence. Middelhoek has attributed this high remanence to the large number...

Most traditional strong magnetic inspection equipment has disadvantages such as big excitation devices, high weight, low detection precision, and inconvenient operation. This paper presents the design of a giant magneto-resistance (GMR) sensor array collection system. The remanence signal is collected to acquire two-dimensional magnetic flux leakage (MFL) data on the surface of wire ropes. Thro...

A unique bulk-origin perpendicular magnetic anisotropy (PMA) is reported in thin films of the cubic ferromagnetic semiconductor GdxSm1−xN. PMA behavior clearly signaled by in-vs-out-of-plane hysteresis showing out-of-plane remanence ∼80% saturation magnetization with up to 30% Gd. Anomalous Hall effect data show further that conduction-band spin imbalance shows complete 100% retain half-metalli...