Crystal growth and characterizations of ErRh3B2

Single crystals of ternary boride ErRh3B2 have been successfully grown by the flux method using molten copper as a solvent; a variety of properties concerning the crystal structure and chemical states of the compound were investigated. ErRh3B2 belongs to a monoclinic system isomorphous with ErIr3B2: space group C2/m, a=0.5355(1), b=0.9282(1), c=0.3102(1) nm and beta=90.89(3)degrees. A superlattice appears along both the a and c axes with periods of 3a and 6c respectively. X-ray photoelectron spectroscopic study indicates that boron acts as an electron donor. According to the differential thermal analysis in air, the oxidation of the compound starts at 373 degrees C. The weight gain of the sample after heating in air up to 1200 degrees C is 15.44%, and the mixed phase of ErBO3 and Rh is confirmed by X-ray diffraction measurement. The value of the micro-Vickers hardness for (001) and (100) faces of the crystals is 11.3-12.0 GPa and 10.4-10.9 GPa respectively.