The development of ferromagnetism in Mn-doped Bi2Te3 is characterized through measurements on a series of single crystals with different Mn content. Scanning tunneling microscopy analysis shows that the Mn substitutes on the Bi sites, forming compounds of the type Bi2−xMnxTe3, and that the Mn substitutions are randomly distributed, not clustered. Mn doping first gives rise to local magnetic mom...

Using first-principles calculations based on gradient corrected density functional theory we show that an otherwise distorted icosahedric Mn(13) ferrimagnetic cluster, when doped with six B or C atoms, transforms into a ferromagnetic cuboctahedral cluster with a magnetic moment that is an order of magnitude larger than that of the pure Mn(13) cluster. The origin of this magnetic transition is a...

an irreversible stirling heat pump cycle using ferromagnetic materials as a cyclic working substance is established. the influences of finite-rate heat transfer, heat leak, regeneration time, regenerative lossand the internal irreversibility on the cyclic performance of magnetic heat pumps are taken into account. on the basis of the thermodynamic properties of ferromagnetic materials, the perfo...

We have investigated the static and dynamical response of magnetic clusters in Co0.2Zn0.8Fe1.6Ti0.4O4 spinel oxide, where a sequence of magnetic phase transitions, i.e, paramagnetic(PM) to ferromagnetic (FM) state at TC ≤ 270K and ferromagnetic to canted spin glass (CSG) state at Tf ≤ 125K is observed. The time dependence of remanent magnetization shows a non-equilibrium spin dynamics in the CS...

We investigate the electronic and cohesive properties of the hexagonal and cubic Laves phases of Fe2Ti by ab initio band structure calculations. In particular the stability range of these compounds is studied. In the volume range considered, the state of lowest energy is hexagonal (C14) and exhibits antiferromagnetic order. However, we find a slightly higher in energy lying ferromagnetic state ...

We report observations of tunneling anisotropic magnetoresitance (TAMR) in vertical tunnel devices with a ferromagnetic multilayer-(Co/Pt) electrode and a nonmagnetic Pt counterelectrode separated by an AlOx barrier. In stacks with the ferromagnetic electrode terminated by a Co film the TAMR magnitude saturates at 0.15% beyond which it shows only weak dependence on the magnetic field strength, ...

Single electron electronics is now well developed, and allows the manipulation of electrons one-by-one as they tunnel on and off a nanoscale conducting island. In the past decade or so, there have been concerted efforts in several laboratories to construct single electron devices incorporating ferromagnetic components in order to introduce spin functionality. The use of ferromagnetic electrodes...

We investigate the quantum phase transition of itinerant ferromagnets. It is shown that correlation effects in the underlying itinerant electron system lead to singularities in the order parameter field theory that result in an effective long-range interaction between the spin fluctuations. This interaction turns out to be generically antiferromagnetic for clean systems. In disordered systems a...

The effects of bond randomness on the ground-state structure, phase diagram and critical behavior of the square lattice ferromagnetic Blume-Capel (BC) model are discussed. The calculation of ground states at strong disorder and large values of the crystal field is carried out by mapping the system onto a network and we search for a minimum cut by a maximum flow method. In finite temperatures th...

In this paper we present a study of magnetic order of quantum Heisenberg spins on pyrochlore type lattices: a lattice of corner sharing tetrahedra. We use the Cluster Variation Approximation with the tetrahedron as basic cluster. We find that in case of anti-ferromagnetic nearest–neighbour exchange there is no long–range spin order at any finite temperature for any spin s. For ferromagnetic exc...