Slow spin tunneling in the paramagnetic phase of the pyrochlore Nd2Sn2O7

Abstract

The insulating pyrochlore compound Nd2Sn2O7 has been shown to undergo a second order magnetic phase transition at Tc ~ 0.91 K to a noncoplanar all-in--all-out magnetic structure of the Nd3+ magnetic moments. An anomalously slow paramagnetic spin dynamics has been evidenced from neutron backscattering and muon spin relaxation (muSR). In the case of muSR this has been revealed through the strong effect of a 50 mT longitudinal field on the spin-lattice relaxation rate. Here, motivated by a recent successful work performed for Yb2Ti2O7 and Yb2Sn2O7, analyzing the shape of the muSR longitudinal polarization function, we substantiate the existence of extremely slow paramagnetic spin dynamics in the microsecond time range for Nd2Sn2O7. Between 1.7 and 7 K, this time scale is temperature independent. This suggests a double spin-flip tunneling relaxation mechanism to be at play, probably involving spin substructures such as tetrahedra. Unexpectedly, the standard deviation of the field distribution at the muon site increases as the system is cooled. This exotic spin dynamics is in sharp contrast with the dynamics above 100 K which is driven by the Orbach relaxation mechanism involving single Nd3+ magnetic moments.

arXiv comment7 pages, 6 figures

References in corpus (24)

• Magnetic Pyrochlore Oxides
• Quantum Spin Ice: A Search for Gapless Quantum Spin Liquids in Pyrochlore Magnets
• Quantum Excitations in Quantum Spin Ice
• Evidence for a Gapped Spin-Liquid Ground State in a Kagome Heisenberg Antiferromagnet
• Quantum spin ices and topological phases from dipolar-octupolar doublets on the pyrochlore lattice
• Quantum fluctuations in the effective pseudospin-1/2 model for magnetic pyrochlore oxides
• Magnetic-Moment Fragmentation and Monopole Crystallization
• Quantum Melting of Spin Ice: Emergent Cooperative Quadrupole and Chirality
• Spin dynamics and magnetic order in magnetically frustrated Tb2Sn2O7
• Spin Waves and Quantum Criticality in the Frustrated XY Pyrochlore Antiferromagnet Er2Ti2O7
• Dimensional Evolution of Spin Correlations in the Magnetic Pyrochlore Yb2Ti2O7
• Direct evidence for a dynamical ground state in the highly frustrated Tb${}_2$Sn${}_2$O${}_7$ pyrochlore
• Nd2Sn2O7: an all-in-all-out pyrochlore magnet with no divergence-free field and anomalously slow paramagnetic spin dynamics
• Quantum spin configurations in Tb2Ti2O7
• Slow spin relaxation in a highly polarized cooperative paramagnet
• Short-range magnetic ordering process for the triangular lattice compound NiGa2S4: a positive muon spin rotation and relaxation study
• Absence of magnetic order in Yb3Ga5O12: relation between phase transition and entropy in geometrically frustrated materials
• Evidence for unidimensional low-energy excitations as the origin of persistent spin dynamics in geometrically frustrated magnets
• A novel type of splayed ferromagnetic order observed in Yb2Ti2O7
• Spin dynamics of the ordered dipolar-octupolar pseudospin-${}^1{/}_2$ pyrochlore Nd${}_2$Zr${}_2$O${}_7$ probed by muon spin relaxation
• Investigation of the magnetic fluctuations in Tb${}_2$Sn${}_2$O${}_7$ ordered spin ice by high resolution energy-resolved neutron scattering
• Spin Fluctuations from Hertz to Terahertz on a Triangular Lattice
• Anomalously slow spin dynamics and short-range correlations in the quantum spin ice systems Yb2Ti2O7 and Yb2Sn2O7
• Magnetic order, spin waves and fluctuations in the triangular antiferromagnet La2Ca2MnO7

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