Universität zu Köln

Ackermann, M., Bruening, D., Lorenz, T., Becker, P. and Bohaty, L. (2013). Thermodynamic properties of the new multiferroic material (NH4)(2)[FeCl5(H2O)]. New J. Phys., 15. BRISTOL: IOP PUBLISHING LTD. ISSN 1367-2630

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Abstract

(NH4)2[FeCl5(H2O)], a member of the family of antiferromagnetic A(2)[FeX5(H2O)] compounds (X = halide ion and A = alkali metal or ammonium ion) is classified as a new multiferroic material. We report the onset of ferroelectricity below similar or equal to 6.9K within an antiferromagnetically ordered state (T-N similar or equal to 7.25 K). The corresponding electric polarization can drastically be influenced by applying magnetic fields. Based on measurements of pyroelectric currents, dielectric constants and magnetization we characterize the magnetoelectric, dielectric and magnetic properties of (NH4)(2)[FeCl5(H2O)]. By combining these data with measurements of thermal expansion, magnetostriction and specific heat, we derive detailed magnetic field versus temperature phase diagrams. Depending on the direction of the magnetic field up to three different multiferroic phases are identified, which are separated by a magnetically ordered, but non-ferroelectric phase from the paramagnetic phase. Besides these low-temperature transitions, we observe an additional phase transition at similar or equal to 79 K, which we suspect to be of structural origin.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Ackermann, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Bruening, D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Lorenz, T. UNSPECIFIED UNSPECIFIED UNSPECIFIED Becker, P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Bohaty, L. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-470299
DOI:	10.1088/1367-2630/15/12/123001
Journal or Publication Title:	New J. Phys.
Volume:	15
Date:	2013
Publisher:	IOP PUBLISHING LTD
Place of Publication:	BRISTOL
ISSN:	1367-2630
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language (NH4)2FECL5.H2O; TRANSITION; BEHAVIOR; SERIES Multiple languages Physics, Multidisciplinary Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/47029