We study, by means of magnetic susceptibility and magnetic aging experiments, the nature of the glassy magnetic dynamics in arrays of Co nanoparticles, self-organized in N layers from N = 1 (two-dimensional limit) up to N = 20 (three-dimensional limit). We find no qualitative differences between the magnetic responses measured in these two limits, in spite of the fact that no spin-glass phase i...

From muon spin relaxation spectroscopy experiments, we show that the sharp peak (lambda-type anomaly) detected by specific heat measurements at 54 mK for the ytterbium gallium garnet compound, Yb3Ga5O12, does not correspond to the onset of a magnetic phase transition, but to a pronounced building up of dynamical magnetic pair correlations. Beside the lambda anomaly, a broad hump is observed at ...

A variable temperature neutron and synchrotron diffraction study has been performed on the giant magnetoresistant oxypnictides LMnAsO (L=La, Nd). The low-temperature magnetic structures have been studied, and results show a spin reorientation of the Mn2+ spins below TN (Nd) for NdMnAsO. The Mn2+ spins rotate from alignment along c to alignment into the basal plane, and the Mn2+ and Nd3+ moments...

We investigated magnetoelastic coupling through the field-driven transition to the fully polarized magnetic state in quasi-two-dimensional [Cu(HF2)(pyz)2]BF4 by magnetoinfrared spectroscopy. This transition modifies out-of-plane ring distortion and bending vibrational modes of the pyrazine ligand. The extent of these distortions increases with the field, systematically tracking the low-temperat...

in this work, one and two-dimensional lattices are studied theoretically by a statistical mechanical approach. the nearest and next-nearest neighbor interactions are both taken into account, and the approximate thermodynamic properties of the lattices are calculated. the results of our calculations show that: (1) even though the next-nearest neighbor interaction may have an insignificant effect...

We present results of dc magnetisation study showing that the low temperature antiferromagnetic state in various CeFe2-based pseudobinary alloys can be transformed into ferromagnetic state through a magnetic field induced phase transition. We highlight the presence of hysteresis and phase coexistence across this metamagnetic transition and argue that the observed phase transition is of first or...

The magnetocaloric effect (MCE) is an intrinsic thermal response of all magnetic solids which has a direct and strong correlation with the corresponding magnetic phase transition. It has been well recognized that the magnetic phase transition can be tuned by adjusting applied pressure. Therefore, we perform the high hydrostatic pressure magnetization measurements (up to 1.4 GPa) on a recently r...

We have measured low field dc and low frequency ac magnetic properties of high quality magnetite single crystals with continuously reading high resolution SQUID magnetometer in a temperature range of 5 – 150 K. In these data several features can be observed: the anisotropy point around 130 K, Verwey transition near 122 K, glass-like transition around 40 K and finally anomalous magnetic behaviou...

The zero-temperature conductivity of Si:B with dopant concentrations near the metal-insulator transition exhibits scaling as a function of magnetic field with an anomalously large crossover exponent. The large value of d is associated with unusual behavior of the magnetoconductance, which vanishes as a power law approaching the transition. This demonstrates that Si:B, which has an anomalous cri...

We present a comprehensive study relating the nanostructure of Ge0.95Mn0.05 films to their magnetic properties. The formation of ferromagnetic nanometer-sized inclusions in a defect-free Ge matrix fabricated by low-temperature molecular beam epitaxy is observed down to substrate temperatures TS as low as 70 °C. A combined transmission electron microscopy and electron energy-loss spectroscopy an...