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The manganocuprate compound Gd3Ba2Mn2Cu2O12 (Gd-3222) has been synthesized by conventional solid state reaction method and its magnetic behavior has been studied by dc and ac magnetization (M) and heat capacity (C) measurements as a function of temperature (T). This compound crystallizes in a tetragonal structure (space group I4/mmm). We find that this compound exhibits three magnetic transitions, around 2.5, 4.8 and 9 K, as inferred from dc and ac magnetic susceptibility (chi) data. However, no evidence for a well-defined lambda-anomaly is found in C(T) above 1.8 K, though there is a gradual upturn below about 10 K. An application of a magnetic field results in a peak around 5K, while ac chi appears to show a very weak frequency dependence below 9 K. Isothermal M curve at 1.8 K exhibits a weak hysteresis without any evidence for saturation even at fields as high as 120 kOe. These results imply that this compound undergoes a spin-glass-like freezing at low temperatures, though the exact nature of the magnetic transition at 10 K is not clear. The magnitude of the magnetocaloric effect, as inferred from M and C data, is quite large over a wide temperature range below 50 K peaking around 4 K.
Dielectric response has been studied for a new manganocuprate, Gd3Ba2Mn2Cu2O12 (Gd3222) as a function of temperature (100 - 300 K) and frequency (75 kHz to 1 MHz). The dielectric constant (e) exhibits a two step increase (two peaks) in e(T) with incr
The polycrystalline form of the compound, Tb5Si3, crystallizing in Mn5Si3-type hexagonal structure, which was earlier believe to order antiferromagnetically below 69 K, has been recently reported by us to exhibit interesting magnetoresistance (MR) an
We report the observation of anomalies in the longitudinal magnetoresistance of tensile-strained (Ga,Mn)As epilayers with perpendicular magnetic anisotropy. Magnetoresistance measurements carried out in the planar geometry (magnetic field parallel to
We report the magnetic, heat-capacity, dielectric and magnetodielectric (MDE) behaviour of a Haldane spin-chain compound containing light rare-earth ion, Nd2BaNiO5, in detail, as a function of temperature (T) and magnetic field (H) down to 2 K. In ad
The design and fabrication of materials that exhibit both semiconducting and magnetic properties for spintronics and quantum computing has proven difficult. Important starting points are high-purity thin films as well as fundamental theoretical under