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The magnetic investigations of potassium holmium double tungstate KHo(WO4)2 have been performed. The results of measurements of magnetic susceptibility and magnetization as a function of temperature (T from 0.3 K up to 100 K) and magnetic field (up to 1.5 T) are presented. A strong anisotropy of magnetic properties was found. The magnetic measurements data were used to calculate the interaction energy. It was shown that the interactions between nearest neighbors Ho3+ ions have antiferromagnetic character. [ABSTRACT FROM AUTHOR]

The specific heat of ARE(WO4)2, where A=K, Rb and RE=Y, Nd, Gd, Yb, and Lu single crystals, has been studied. The samples were grown using the Top Seeded Solution Growth – Slow Cooling (TSSG-SC) method, and the resulting crystal structure data was tabulated. The specific heat measurements as a function of temperature in the range from 0.35 to 385 K are presented. Above 2 K, the specific heat behavior can be described by the phonon contribution while below 2 K, an anomalous increase in specific heat, attributed to the proximity of magnetic phase transitions, was observed. [ABSTRACT FROM AUTHOR]

The magnetic investigations as a function of the temperature and magnetic field for the rubidium neodymium double tungstate RbNd(WO4)2 single crystal have been performed. The magnetization was measured in the temperature range from 4.2 to 100 K and for the magnetic field up to 1.5 T. The crystal field and exchange parameters were found. [ABSTRACT FROM AUTHOR]

The electron paramagnetic resonance (EPR) of Yb3+ ions in a KY(WO4)2 single crystal was investigated at T=4.2 K and fixed frequency of 9.38 GHz. The resonance absorption observed on the lowest Kramers doublet represents the complex superposition of three spectra, corresponding to the ytterbium isotopes with different nuclear moments. The EPR spectrum is characterized by a strong anisotropy of the g-factors. The temperature dependence of the g-factors is shown to be caused by the strong spin-orbital and orbital-lattice coupling. The resonance lines broaden with increasing temperature due to the short spin-lattice relaxation times. [ABSTRACT FROM AUTHOR]

The optical absorption and luminescence properties of potassium-holmium and potassium-erbium double tungstates have been studied. It is established that the potassium-holmium double tungstate belongs to a group of biaxial and pleochromic crystals. The emission and excitation spectra of the KHo(WO4)2 and KEr(WO4)2 single crystals were measured at room temperature. [ABSTRACT FROM AUTHOR]

The temperature dependence of the magnetic susceptibility along the principal magnetic axes of rubidium–dysprosium tungstate RbDy(WO[sub 4])[sub 2] is measured in the temperature interval 0.5–300 K. Strong anisotropy of the susceptibility is observed at all temperatures in that range. At T[sub N]=0.8 K the susceptibility along all three magnetic axes exhibits a sharp anomaly due to the phase transition to a magnetically ordered state. At 0.5 K the measured field dependence of the magnetization along all three axes demonstrates a metamagnetic orientational phase transition in the directions of the magnetic axes y and z. Another type of anomaly of the magnetic susceptibility is observed at temperatures of around 5, 8, and 50 K. Analysis shows that these anomalies correspond to structural phase transitions in this compound. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Electron paramagnetic resonance is detected optically via the change of magnetic circular dichroism under microwaves at 35 GHz. The technique is applied to Bi 12 GeO 20 samples co-doped with vanadium and a second transition metal (Cr, Mn, Co, Cu). The optical and magnetic properties of several paramagnetic defects (V Ge 4+ and Cr Ge 4+ ) are directly correlated. The basic photochromic processes occuring in samples doped with V, Mn, and Mn+V are explained. The V Ge 4+/5+ level is positioned roughly 2.2 eV above the valence band. [ABSTRACT FROM AUTHOR]

The potassium holmium double tungstate was prepared by using top seeded solution growth technique. Structural investigations have been performed at room temperature. The KHo(WO4)2 single crystal belongs to the monoclinic space group C2=c with the unit-cell parameters: a = 10:624(2) Å, b = 10:352(2) Å, c = 7:5434(15) Å, β = 130:78(3)°, and Z = 4. The atomic coordinates, isotropic and anisotropic displacement parameters and interionic distances for the studied structure were determined. [ABSTRACT FROM AUTHOR]