Field Dependence of the Magnetic Propagation Vector of the Heavy Fermion Compound CeCu2Ge2 Studied by Neutron Diffraction

Loewenhaupt, M.; Schneidewind, A.; Faulhaber, E.; Schmalzl, K.; Rotter, M.; Doerr, M.; Geselbracht, P.

doi:10.1016/j.phpro.2015.12.028

Journal Article

FZJ-2016-00393

Field Dependence of the Magnetic Propagation Vector of the Heavy Fermion Compound CeCu2Ge2 Studied by Neutron Diffraction

Loewenhaupt, M. (Corresponding author) ; Geselbracht, P. ; Faulhaber, E. ; Rotter, M. ; Doerr, M. ; Schmalzl, K.FZJ* ; Schneidewind, A.FZJ*

2015
Elsevier Amsterdam [u.a.]

Physics procedia 75, 230 - 237 (2015) [10.1016/j.phpro.2015.12.028]

This record in other databases:

Please use a persistent id in citations: http://hdl.handle.net/2128/9688 doi:10.1016/j.phpro.2015.12.028

Abstract: CeCu2Ge2, the counterpart of the heavy-fermion superconductor CeCu2Si2, exhibits an in-commensurate antiferromagnetically long-range ordered ground state with τ = (0.28 0.28 0.54) below TN = 4.15K. The magnetism is strongly affected by a Kondo screening of the Ce 4f-moments by conduction electrons. The similar energy scale of both, Kondo and exchange interactions, results in a complex magnetic phase diagram and gives rise to potential quantum critical phenomena at very low temperatures. We present elastic neutron diffraction data obtained on a CeCu2Ge2 single crystal employing the cold triple axis spectrometer PANDA at MLZ and the diffractometer D23 at ILL.The field dependence of the magnetic propagation vector was measured at T ≤ 400 mK in the [110]/[001] plane with vertical magnetic fields applied along [1̄10]. We observe a low-field incommensurate magnetic phase AF1, a first order phase transition around 7.8 T with the coexistence of two phases AF1 and AF2 with slightly different propagation vectors, the disappearance of AF1 at 8 T and the existence of AF2 up to 12 T with a possible modification at 10 T. At 12.6 T, yet still well below the value of 26 T of the saturation for magnetic fields in [110] direction, the AF2-type magnetic order is lost and magnetic intensities are not to be found at incommensurate positions in the [110]/[001] plane any more. These new results contradict a previously suggested scenario with a QCP located at 8 T and contribute new information to the B − T phase diagram of CeCu2Ge2 in [110] direction.

Keyword(s): Basic research (1st) ; Key Technologies (1st) ; Condensed Matter Physics (2nd) ; Magnetism (2nd)

Classification: