This title appears in the Scientific Report :
2014
Please use the identifier:
http://hdl.handle.net/2128/8085 in citations.
Please use the identifier: http://dx.doi.org/10.1103/PhysRevB.89.174431 in citations.
Approaching the true ground state of frustrated A-site spinels: A combined magnetization and polarized neutron scattering study
Approaching the true ground state of frustrated A-site spinels: A combined magnetization and polarized neutron scattering study
We re-investigate the magnetically frustrated, diamond-lattice-antiferromagnet spinels FeAl2O4 and MnAl2O4 using magnetization measurements and diffuse scattering of polarized neutrons. In FeAl2O4, macroscopic measurements evidence a “cusp” in zero field-cooled susceptibility around 13 K. Dynamic ma...
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Personal Name(s): | Nair, Harikrishnan (Corresponding Author) |
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Fu, Zhendong / Voigt, Jörg / Su, Yixi / Brückel, Thomas | |
Contributing Institute: |
JCNS-FRM-II; JCNS-FRM-II JARA-FIT; JARA-FIT Streumethoden; PGI-4 Streumethoden; JCNS-2 |
Published in: | Physical Review B Physical review / B, 89 89 (2014 2014) 17 17, S. 174431 174431 |
Imprint: |
College Park, Md.
APS
2014
|
DOI: |
10.1103/PhysRevB.89.174431 |
Document Type: |
Journal Article |
Research Program: |
JCNS In-house Research with PNI Neutrons Exploratory materials and phenomena Spin-based and quantum information |
Subject (ZB): | |
Link: |
OpenAccess |
Publikationsportal JuSER |
Please use the identifier: http://dx.doi.org/10.1103/PhysRevB.89.174431 in citations.
We re-investigate the magnetically frustrated, diamond-lattice-antiferromagnet spinels FeAl2O4 and MnAl2O4 using magnetization measurements and diffuse scattering of polarized neutrons. In FeAl2O4, macroscopic measurements evidence a “cusp” in zero field-cooled susceptibility around 13 K. Dynamic magnetic susceptibility and memory effect experiments provide results that do not conform with a canonical spin-glass scenario in this material. Through polarized neutron-scattering studies, absence of long-range magnetic order down to 4 K is confirmed in FeAl2O4. By modeling the powder averaged differential magnetic neutron-scattering cross section, we estimate that the spin-spin correlations in this compound extend up to the third nearest-neighbor shell. The estimated value of the Landé g factor points towards orbital contributions from Fe2+. This is also supported by a Curie-Weiss analysis of the magnetic susceptibility. MnAl2O4, on the contrary, undergoes a magnetic phase transition into a long-range ordered state below ≈40 K, which is confirmed by macroscopic measurements and polarized neutron diffraction. However, the polarized neutron studies reveal the existence of prominent spin fluctuations co-existing with long-range antiferromagnetic order. The magnetic diffuse intensity suggests a similar short-range order as in FeAl2O4. Results of the present work support the importance of spin-spin correlations in understanding magnetic response of frustrated magnets like A-site spinels which have predominant short-range spin correlations reminiscent of the “spin-liquid” state. |