In magnetic alloys, the effect of finite temperature magnetic excitations on phase stability below the Curie temperature is poorly investigated, although many systems undergo phase transitions in this temperature range. We consider random Ni-rich Fe-Ni alloys, which undergo chemical order-disorder transition approximately 100 K below their Curie temperature, to demonstrate from ab initio calcul...

The sputter deposited ~Pt/Co/Pt/Ni! multilayer films were studied as possible alternative low Curie temperature multilayers for magneto-optical recording. The Curie temperatures of these multilayers were found to be between 150 and 300 °C, which are much lower than those of Co/Pt multilayers or ~Co,Ni!/Pt multilayers. The coercivities of these multilayers were between 450 and 800 Oe. The Kerr s...

We estimate, using high-temperature series expansions, the transition temperatures of the spin 2 , 1 and 3 2 Heisenberg ferromagnet and antiferromagnet in three dimensions. The manner in which the difference between Curie and Néel temperatures vanishes with increasing spin quantum number is investigated. It is well known that in classical spin models, such as the Ising and classical Heisenberg ...

The electronic structure of diluted (Ga,Mn)As magnetic semiconductors in the presence of As-antisites and magnetic disorder is studied within the framework of the local spin density approximation. Both the chemical and magnetic disorders are treated using the coherent potential approximation. A ground state with partial disorder in the local moments and with a reduced total magnetic moment appe...

The kinetic coefficient associated with the domain-wall motion exhibits a critical speeding up close to T,. Damping by longitudinal spin-spin-relaxation within "linear" walls is proposed to explain this intrinsic phenomenon. The present understanding of structure, formation and dynamics of ferromagnetic domains is still incomplete. In essence, the difficulties arise from the nonlocal and anisot...

Based on a previously reported double-resonance mechanism, we present an analytical expression of the effective exchange interaction between impurity moments of transition-metal elements introduced in semiconductors. It is shown that the exchange interaction is enhanced by several orders of magnitude as compared with the ordinary RKKY interaction when the Fermi level and impurity states are clo...