Magnetic and electron-transport properties of YMB₄ (M=Cr, Fe, and Co)

Materials exhibiting quantum phenomena have attracted much attention due to their exotic properties. We have studied the structural, magnetic and electrical transport properties of the YMB₄ series (M= Cr, Fe, and Co) of compounds. These materials are highly stable, hard, and have refractory and thermoelectric properties. Recent investigations indicate that these materials host quantum magnetism and support the formation of dimers among the magnetic ions [1]. All three compounds in our study have an orthorhombic crystal structure. Rietveld refinement of the x-ray diffraction patterns has been carried out to determine unit cell parameters, using the space group Pbam. The lattice parameters decrease when moving from M= Cr to Co. The electrical transport properties have been measured between 2K and room temperature. The temperature variation of resistivity shows a metallic behaviour below room temperature in all three compounds, and weak magnetoresistance at 2.5 K. Carrier concentration and Hall coefficients have been determined through the conventional Hall effect measurements. The magnetic studies indicate that all these materials are non-magnetic, however, a weak magnetic signal from small amount of impurities is observed.