Large magnetic field-induced spectral weight enhancement of high-energy spin excitations in La1.88Sr0.12CuO4 -: art. no. 107009

We report electronic Raman scattering experiments on a superconducting La1.88Sr0.12CuO4 single crystal in a magnetic field. At low temperatures, the spectral weight of the high-energy two-magnon peak increases linearly with field and is amplified by a factor of more than two at 14 T. The effect disappears at elevated temperatures and is not present in undoped La2CuO4. This observation is discussed in terms of an electronically inhomogeneous state in which the field enhances the volume fraction of a phase with local antiferromagnetic order at the expense of the superconducting phase.