Dipolar-octupolar Ising antiferromagnetism in ${\text{Sm}}_2{\text{Ti}}_2{\text{O}}_7$ : A moment fragmentation candidate

Journal Article · Wed Sep 05 00:00:00 EDT 2018 · Physical Review B

DOI:https://doi.org/10.1103/PhysRevB.98.100401· OSTI ID:1470878

Mauws, Cole ^[1]; Hallas, A. M. ^[2]; Sala, Gabriele  ^[3]; Aczel, Adam A.  ^[3]; Sarte, P. M. ^[4]; Gaudet, J. ^[5]; Ziat, D. ^[6]; Quilliam, J. A. ^[6]; Lussier, J. A. ^[7]; Bieringer, M. ^[7]; Zhou, H. D. ^[8]; Wildes, A. ^[9]; Stone, Matthew B.  ^[3]; Abernathy, Douglas L.  ^[3]; Luke, G. M. ^[10]; Gaulin, B. D. ^[11]; Wiebe, Christopher R. ^[12]

---

1. Univ. of Manitoba, Winnipeg, Manitoba (Canada). Dept. of Chemistry; Univ. of Winnipeg, Winnipeg, Manitoba (Canada). Dept. of Chemistry
2. McMaster Univ., Hamilton, ON (Canada). Dept. of Physics and Astronomy; Rice Univ., Houston, TX (United States). Dept. of Physics and Astronomy and Rice Center for Quantum Materials
3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Neutron Scattering Division
4. Univ. of Edinburgh, Scotland (United Kingdom). School of Chemistry; Univ. of Edinburgh, Scotland (United Kingdom). Centre for Science at Extreme Conditions
5. McMaster Univ., Hamilton, ON (Canada). Dept. of Physics and Astronomy
6. Univ. de Sherbrooke, Sherbrooke, Québec (Canada). Inst. Quantique and Dépt. de Physique
7. Univ. of Manitoba, Winnipeg, Manitoba (Canada). Dept. of Chemistry
8. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Physics and Astronomy; Florida State Univ., Tallahassee, FL (United States). National High Magnetic Field Lab. (MagLab)
9. Inst. Laue-Langevin, Grenoble (France)
10. McMaster Univ., Hamilton, ON (Canada). Dept. of Physics and Astronomy; Canadian Inst. for Advanced Research, Toronto, Ontario (Canada); TRIUMF, Vancouver, BC (Canada)
11. McMaster Univ., Hamilton, ON (Canada). Dept. of Physics and Astronomy; Canadian Inst. for Advanced Research, Toronto, Ontario (Canada)
12. Univ. of Manitoba, Winnipeg, Manitoba (Canada). Dept. of Chemistry; Univ. of Winnipeg, Winnipeg, Manitoba (Canada). Dept. of Chemistry; McMaster Univ., Hamilton, ON (Canada). Dept. of Physics and Astronomy; Canadian Inst. for Advanced Research, Toronto, Ontario (Canada)

Over the past two decades, the magnetic ground states of all rare-earth titanate pyrochlores have been extensively studied, with the exception of ${\text{Sm}}_2{\text{Ti}}_2{\text{O}}_7$. This is, in large part, due to the very high absorption cross section of naturally occurring samarium, which renders neutron scattering infeasible. To combat this, we have grown a large, isotopically enriched single crystal of ${\text{Sm}}_2{\text{Ti}}_2{\text{O}}_7$. Using inelastic neutron scattering, we determine that the crystal field ground state for Sm3+ is a dipolar-octupolar doublet with Ising anisotropy. Neutron diffraction experiments reveal that ${\text{Sm}}_2{\text{Ti}}_2{\text{O}}_7$ orders into the all-in, all-out magnetic structure with an ordered moment of 0.44(7)μ_B below TN=0.35 K, consistent with expectations for antiferromagnetically coupled Ising spins on the pyrochlore lattice. Zero-field muon spin relaxation measurements reveal an absence of spontaneous oscillations and persistent spin fluctuations down to 0.03 K. In conclusion, the combination of the dipolar-octupolar nature of the Sm³⁺ moment, the all-in, all-out ordered state, and the low-temperature persistent spin dynamics make this material an intriguing candidate for moment fragmentation physics.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1470878
• Alternate ID(s): OSTI ID: 1468836
• Journal Information: Physical Review B, Vol. 98, Issue 10; ISSN 2469-9950
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY