Paramagnetic Resonance Absorption in Two Copper Salts at Wavelengths of 5.4 mm and 6.6 mm

Paramagnetic resonance absorption in single crystals of CuSO 4 ·5H 2 O and K 2 CuCl 4 ·2H 2 O has been investigated at wavelengths of 5.4 mm and 6.6 mm. The shapes of absorption lines vary remarkably with orientation of the crystal in the magnetic field. This is interpreted in terms of exchange interaction between copper ions. The line shapes are compared with result calculated recently by Anderson. And then the exchange frequencies are estimated to be 1.0×10 10 and 1.1×10 10 for CuSO 4 ·5H 2 O and K 2 CuCl 4 ·2H 2 O respectively.