OBSERVATION OF NONEQUILIBRIUM BOSE-CONDENSATION OF QUASIPHONONS EXCITED BY A NOISY MICROWAVE PUMP

The parametric excitation of quasiphonons in the antiferromagnet FeBO3 by a noisy microwave field has been studied. There are two critical p ump amplitudes: one corresponding to the onset of nonlinear absorption of microwave power and one above which strong phase correlations, i.e ., a nonequilibrium Bose condensate, arise in the system of excited qu asiphonons. (C) 1994 American Institute of Physics.