A flop of electric polarization from P c (Pc) to P a (Pa) is observed in MnTiO3 as a spin flop transition is triggered by a c-axis magnetic field, H c =7 T. The critical magnetic field H c for Pa is significantly reduced in Mn1−xNixTiO3 (x=0.33). Pa and Pc have been observed with both H c and H a . Neutron diffraction measurements revealed similar magnetic arrangements for the two compositions where the ordered spins couple antiferromagnetically with their nearest intra-and inter-planar neighbors. In the x=0.33 system, the uniaxial and planar anisotropies of Mn 2+ and Ni 2+ compete and give rise to a spin reorientation transition at TR. A magnetic field, H c , aligns the spins along c for TR

Polycrystalline Pb3TeCo3V2O14, a structural analogue of the multiferroic Ba3NbFe3Si2O14, was synthesized and characterized using X-ray diffraction, magnetic susceptibility, specific heat, dielectric constant, and neutron diffraction. Magnetic susceptibility, specific heat capacity measurements, and bond valence analysis confirmed that the V5+ ion is nonmagnetic, while Co2+ is in its high spin state (S = 3/2). Two magnetic transitions were seen at T N1 = 8.6 K and T N2 = 6.0 K where the spins first adopt a magnetic structure with propagation vector k⃗ = (0.752,0,1/2) and reorder into a commensurate structure with propagation vector k⃗ = (5/6,5/6,1/2). Changes in the dielectric constant at both magnetic phase transitions suggest that magnetoelectric coupling exists in Pb3TeCo3V2O14.

We investigated the magnetic phase diagram of single crystals of SrNdFeO 4 by measuring the magnetic properties, the specific heat and the dielectric permittivity. The system has two magnetically active ions, Fe 3+ and Nd 3+ . The Fe 3+ spins are antiferromagnetically ordered below 360 K with the moments lying in the ab plane, and undergo a reorientation transition at about 35-37 K to an antiferromagnetic order with the moments along the c axis. A short-range, antiferromagnetic ordering of Nd 3+ along the c axis was attributed to the reorientation of Fe 3+ followed by a long-range ordering at lower temperature [Oyama et al., J. Phys.: Condens. Matter. 16, 1823]. At low temperatures and magnetic fields above 8 T, the Nd 3+ moments are completely spin polarized. The dielectric permittivity also shows anomalies associated with spin configuration changes, indicating that this compound has considerable coupling between spin and lattice. A possible magnetic structure is proposed to explain the results.

Synthetic aperture radar(SAR) has been widely used for reconnaissance. It provides high-resolution, day-and-night and weather-independent images for a multitude of applications [1] . Because SAR coherently combines many viewing angles to effectively create a large aperture(narrow beam) radar, the test-bed should be capable of moving straightly SAR sensor for the integration angle to meet resolution. This paper describes the test-bed developed to test and evaluate the SAR performance. It forms high-quality images in real time and saves the raw data for the purpose of post processing on the ground.