We have measured the adiabatic second order elastic constants of two Ni-Mn-Ga magnetic shape memory crystals with different martensitic transition temperatures, using ultrasonic methods. The temperature dependence of the elastic constants has been followed across the ferromagnetic transition and down to the martensitic transition temperature. Within experimental errors no noticeable change in a...

In this paper, the Hartree-Fock method has been formulated to investigate some of the ground state properties of quasi-one-dimensional interacting electron gas in the presence of the magnetic field. The bare coulomb interaction between electrons has been assumed. For this system, we have also computed some of its thermodynamic and magnetic properties such as the energy, pressure, incompressibil...

Using neutron diffraction, 170Yb Mössbauer and muon spin relaxation spectroscopies, we have examined the pyrochlore Yb2Ti2O7, where the Yb3+S' = 1/2 ground state has planar anisotropy. Below approximately 0.24 K, the temperature of the known specific-heat lambda transition, there is no long range magnetic order. We show that the transition corresponds to a first-order change in the fluctuation ...

Recent experimental developments on the electric field effect on magnetism in metallic magnetic materials are reviewed. The change in the electron density at the surface of metallic ultra-thin magnets by the application of an electric field results in modulations of the Curie temperature, magnetic moment, magnetic anisotropy, and domain wall velocity. The study focused on this paper is the elec...

The transport in oxygen-deficient polycrystalline La2/3Sr1/3MnO3−δ thin films deposited on Si(111) substrates using laser ablation is studied by measuring the resistivity and ac magnetic susceptibility over the range 2–300 K. The oxygen deficiency results in a serious shift of the insulating–metal (IM) transition toward the low-temperature side and anomalous transport behaviour over the low-tem...

We present evidence for the existence of magnetic clusters of approximately 20 A in the strongly correlated alloy system CeNi 1-x Cux (0.7<or=x<or=0.2) based on small angle neutron scattering experiments as well as the occurrence of staircaselike hysteresis cycles at very low temperature (100 mK). An unusual feature is the observation of long-range ferromagnetic order below the cluster-glass tr...

Magnetic and electric properties are investigated for the nanosized YMnO3 samples with different grain sizes (25 nm to 200 nm) synthesized by a modified Pechini method. It shows that magnetic and electric properties are strongly dependent on the grain size. The magnetic characterization indicates that with increasing grain size, the antiferromagnetic (AFM) transition temperature increases from ...

Electrical resistivity, dc magnetization, ac magnetic susceptibility, and magnetic relaxation studies of polycrystalline Pr(0.2)La(0.8)Fe(11.4)Al(1.6) compound have been carried out. On the basis of the measurements of isofield magnetization and ac magnetic susceptibility, we provide evidence for phase coexistence (the appearance of the ferromagnetic phase in the antiferromagnetic matrix) rathe...

The available data on the structural and magnetic transitions in multiferroic hexagonal YMnO3 have been reviewed, first making use of the computer programs from the group theoretical ISOTROPY software suite to list possible crystal and magnetic structures, then taking into account the capability of neutron diffraction and other physical methods to distinguish them. This leads to a clear view of...

The dual approach to the Ginzburg-Landau theory of a Bardeen-Cooper-Schrieffer superconductor is reviewed. The dual theory describes a grand canonical ensemble of fluctuating closed magnetic vortices, of arbitrary length and shape, which interact with a massive vector field representing the local magnetic induction. When the critical temperature is approached from below, the magnetic vortices p...