"Persistence of magnons in a site-diluted dimerized frustrated antiferromagnet"

M B Stone: A Podlesnyak, G Ehlers, A Huq, E C Samulon, M C Shapiro and I R Fisher; J. Phys.: Condens. Matter , 09/28/11.

Additional Authors: A Podlesnyak, G Ehlers, A Huq, E C Samulon, M C Shapiro and I R Fisher

Abstract:

We present inelastic neutron scattering and thermodynamic measurements characterizing the magnetic excitations in a disordered spin-liquid antiferromagnet with non-magnetic substitution. The parent compound Ba3Mn2O8 is a dimerized, quasi-two-dimensional geometrically frustrated quantum disordered antiferromagnet. We substitute this compound with non-magnetic V 5+ for the S = 1 Mn5+ ions, Ba3(Mn1−xx)2O8, and find that the singlet–triplet excitations which dominate the spectrum of the parent compound persist for the full range of substitution examined, up to x = 0.3. We also observe additional low-energy magnetic fluctuations which are enhanced at the greatest substitution values.