Sign reversal of the MN-O bond compressibility in La{sub 1.2}Sr{sub 1.8}Mn{sub 2}O{sub 7} below T{sub C}: Exchange striction in the ferromagnetic state
Description/Abstract
The crystal structure of the layered perovskite La{sub 1.2}Sr{sub 1.8}Mn{sub 2}O{sub 7} has been studied under hydrostatic pressure up to {approximately} 6 kbar, in the paramagnetic and ferromagnetic states, with neutron powder diffraction. The compressibility of the Mn-O apical bonds in the double layer of MnO{sub 6} octahedra changes sign from the paramagnetic insulator (PI) to the ferromagnetic metal (FM) state; in the Fm state the Mn-O-Mn linkage between MnO{sub 2} planes expands under applied pressure, whereas they contract in the PI state. This counterintuative behavior is interpreted in terms of exchange striction, which reflect the competition between super- and double-exchange. An increase of the Mn-moment with applied pressure in the FM state is consistent with a positive dT{sub C}/dP, as well as a cant angle {theta}{sub 0} between the magnetizations of neighboring MnO{sub 2} sheets that decreases with pressure.
| Creator/Author: | Argyriou, D.N. ; Mitchell, J.F. ; Chmaissem, O. ; Short, S. ; Jorgensen, J.D. [Argonne National Lab., IL (United States)] ; Goodenough, J.B. [Univ. of Texas, Austin, TX (United States). Center for Material Science and Engineering] |
|---|---|
| Publication Date: | 1997 Mar 01 |
| OSTI Identifier: | OSTI ID: 521660; Legacy ID: DE97007006 |
| Report Number(s): | ANL/MSD/CP--91963; CONF-9703106--1 |
| DOE Contract Number: | W-31109-ENG-38 |
| Other Number(s): | Other: ON: DE97007006; CNN: Grant NSF DMR 91-20000; TRN: 97:018424 |
| Resource Type: | Conference |
| Resource Relation: | Conference: American Physical Society meeting, Kansas City, MO (United States), 17-21 Mar 1997; Other Information: PBD: Mar 1997 |
| Research Org: | Argonne National Lab., IL (United States) |
| Sponsoring Org: | USDOE Office of Energy Research, Washington, DC (United States);National Science Foundation, Washington, DC (United States);Welch (Robert A.) Foundation, Houston, TX (United States) |
| Subject: | 36 MATERIALS SCIENCE; CRYSTAL STRUCTURE; LANTHANUM OXIDES; STRONTIUM OXIDES; MANGANESE OXIDES; PHYSICAL PROPERTIES; PRESSURE DEPENDENCE; CURIE POINT; CHEMICAL BONDS; TEMPERATURE DEPENDENCE |
| Country of Publication: | United States |
| Language: | English |
| Format: | Size: 16 p. |
| Availability: | INIS; OSTI as DE97007006 To purchase this media from NTIS, click here |
| Update Date: | 2009 Nov 12 |
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