OBSERVATIONS OF THE FERROELASTIC DOMAIN-STRUCTURE OF MP5O14 (MLA-TB) BY MEANS OF SCANNING TUNNELING MICROSCOPE, ELECTRON-SPIN-RESONANCE AND X-RAY-DIFFRACTION

The ferroelasticity of rare earth pentaphosphate, MP5O14 (M: La-Tb) belonging to the species mmmF2/m is studied by scanning tunneling microscope (STM), electron spin resonance (ESR) and X-ray diffraction. The temperature dependence (from room temperature to 180-degrees-C) of ferroelastic domain structure and monoclinic beta angle of EuP5O14 was obtained by STM and X-ray diffraction (omega scan technique). The spin Hamiltonian parameters of LaP5014:Cr3+ at 150-degrees-C in the para phase obtained from the ESR spectra are g(x)=g(y)=g(z)=1.97, D=0.45 cm-1 and E=0.05 cm-1. The principal axes of one of the Cr3+ paramagnetic centers are given by the Eulerian angles phi = 15-degrees, theta = 90-degrees and psi = 0-degrees.