Magnetostructural Phase Diagram of Multiferroic (ND₄)₂FeCl₅.H₂O

Technical Report · Mon Feb 13 00:00:00 EST 2017

DOI:https://doi.org/10.2172/1343728· OSTI ID:1343728

Clune, A. ^[1]; Hughey, K. ^[1]; Musfeldt, J. L. ^[1]; Tian, W. ^[2]; Fernandez-Baca, J. ^[2]; Singleton, John ^[3]

---

1. Univ. of Tennessee, Knoxville, TN (United States)
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Spin and polarization flop transitions are fascinating, especially when controlled by external stimuli like magnetic and electric field and accompanied by large material responses involving multiple degrees of freedom. Multiferroics like MnWO₄, TbMnO₃, and Ni₃TeO₆ are flagship examples and owe their remarkable properties, for instance field control of polarization and polarization flops combined with spin helix reorientation, to the anisotropy and heavy centers that bring in spin-orbit coupling. The family of A₂FeX₅.H₂O erythrosiderites (A = K, Rb, NH₄; B = Fe, Mn, Co; X = Cl, Br, H₂O) drew our attention due to the rich chemical tuning possibilities, complex phase diagrams, and topological similarities to oxide multiferroics.1 (NH₄)₂FeCl₅.H₂O is the flagship example (Fig. 1(a)). It displays a high temperature order-disorder transition involving long-range hydrogen bonding of the NH₄⁺ group and two successive low temperature magnetic transitions below which non-collinear magnetic order and ferroelectricity are established.1 In addition to the magnetically-induced electric polarization that arises below 6.9 K (P = 3 μC/m₂ along a and a smaller component along b), applied field reveals a peculiar hysteretic spin flop transition near 4.5 T above which polarization flops from the a- to the c-axis. There are elastic components as well. Taken together, these findings raise questions about the interactions that induce this behavior and whether additional non-equilibrium phases might be accessed under even higher magnetic fields.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC52-06NA25396
• OSTI ID: 1343728
• Report Number(s): LA-UR-17-21125
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
High Magnetic Field Science