TY  - JOUR
AU  - Brüning, Daniel
AU  - Fröhlich, Tobias
AU  - Langenbach, Malte
AU  - Leich, Thomas
AU  - Meven, Martin
AU  - Becker, Petra
AU  - Bohatý, Ladislav
AU  - Grüninger, Markus
AU  - Braden, Markus
AU  - Lorenz, Thomas
TI  - Magnetoelectric coupling in the mixed erythrosiderite [(NH$_4$)$_{1−x}$K$_x$]$_2$[FeCl$_5$(H$_2$O)]
JO  - Physical review / B
VL  - 102
IS  - 5
SN  - 2469-9950
CY  - Woodbury, NY
PB  - Inst.
M1  - FZJ-2020-04850
SP  - 054413
PY  - 2020
AB  - We present a study of the dielectric, structural and magnetic properties of the multiferroic orlinear magnetoelectric substitution series [(NH4)1􀀀xKx]2[FeCl5(H2O)]. Pyroelectric currents, magneticsusceptibilities, and thermodynamic properties were examined on large single crystals of theerythrosiderite compounds and detailed magnetic-eld versus temperature phase diagrams are derivedfor three dierent substitution levels. With increasing potassium concentration the material istuned from a multiferroic (x  0:06) to a linear magnetoelectric (x  0:15) ground state. In contrastto the respective pure parent compounds with x = 0 or 1, however, the ferroelectric or linear magnetoelectricpolarization in none of the substituted samples is switchable by external electric elds,because these samples exhibit a signicant electric polarization already above the magnetic orderingtransition. The polarization arises at a higher-lying structural phase transition that is examined byTHz spectroscopy and by comprehensive neutron-diraction experiments on a deuterated pure singlecrystal. The structural phase transition is attributed to an ordering of NH+4 tetrahedra but doesnot break inversion symmetry in the pure material, while nite K content causes pyroelectricity.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000557288200001
DO  - DOI:10.1103/PhysRevB.102.054413
UR  - https://juser.fz-juelich.de/record/888331
ER  -