Low temperature dielectric properties of phosphate glasses containing nd₂0₃

Measurements of capacitance of phosphate glasses containing Nd203 at temperatures from 1 K to 10 mK are presented. The capacitance varied logarithmically with temperature having a minimum around 250 mK. However, such a behavior completely disappeared in magnetic fields above 5 kOe. The magnetic impurity Nd₂0₃ gives an important contribution to dielectric properties of phosphate glasses. This is the first result to show that a hydroxyl OH in phosphate glasses is in a state which is different from that in silicate glasses.