Abstract
Spin ice is a magnetic analog of H 2 O ice that harbors dense static disorder. Dipolar interactions between classical spins yield a frozen frustrated state with residual configurational Pauling entropy and emergent magnetic monopolar quasiparticles. Introducing quantum fluctuations is of great interest as this could melt spin ice and allow coherent propagation of monopoles. Here, we report experimental evidence for quantum dynamics of magnetic monopolar quasiparticles in a new class of spin ice based on exchange interactions, Pr 2 Zr 2 O 7. Narrow pinch point features in otherwise diffuse elastic neutron scattering reflects adherence to a divergence-free constraint for disordered spins on long time scales. Magnetic susceptibility and specific heat data correspondingly show exponentially activated behaviors. In sharp contrast to conventional ice, however, >90% of the neutron scattering is inelastic and devoid of pinch points furnishing evidence for magnetic monopolar quantum fluctuations.
| Original language | English |
|---|---|
| Article number | 1934 |
| Journal | Nature Communications |
| Volume | 4 |
| DOIs | |
| State | Published - 2013 |
Funding
We thank Y. Karaki, Y. Shimura, T. Sakakibara, K. Kuga, M. Takigawa, T. M. McQueen, S. Koohpayeh, K. Matsuhira, Y. Nambu, A.A. Nugroho, Y. Ohta, S. Onoda, R. Satake, O. Tchernyshyov and Y. Wan for useful discussions. This work is partially supported by Grant-in-Aid for Scientific Research (Nos. 21684019 and 23740259) from JSPS, by Grant-in-Aid for Scientific Research on Priority Areas (No. 19052003) and Grant-in-Aid for JSPS Fellows from MEXT, Japan, by Global COE Program ‘the Physical Sciences Frontier’, MEXT, Japan, by PRESTO of JST, by a Toray Science and Technology Grant and by US-Japan Cooperative Program, ISSP. Work at IQM was supported by the US DoE, office of Basic Energy Sciences, Division of Material Sciences and Engineering under DE-FG02-08ER46544. This work utilized facilities supported in part by the NSF under DMR-0944772. Research conducted at ORNL’s Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy. Part of this work was conducted while CB was a JSPS fellow at ISSP. The use of the Materials Design and Characterization Laboratory at ISSP is gratefully acknowledged.
| Funders | Funder number |
|---|---|
| Scientific User Facilities Division | |
| Toray Science and Technology | |
| US-Japan | |
| National Science Foundation | DMR-0944772 |
| U.S. Department of Energy | |
| Basic Energy Sciences | |
| Division of Materials Sciences and Engineering | DE-FG02-08ER46544 |
| Japan Society for the Promotion of Science | 19052003, 23244074, 25707030 |
| Ministry of Education, Culture, Sports, Science and Technology | |
| Japan Science and Technology Agency | |
| Institute of Solid State Physics, Chinese Academy of Sciences | |
| Precursory Research for Embryonic Science and Technology |