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Zhang J, Ding Z, Tan C, Huang K, Bernal OO, Ho PC, Morris GD, Hillier AD, Biswas PK, Cottrell SP, Xiang H, Yao X, MacLaughlin DE, Shu L. Discovery of slow magnetic fluctuations and critical slowing down in the pseudogap phase of YBa 2Cu 3O y. SCIENCE ADVANCES 2018; 4:eaao5235. [PMID: 29326982 PMCID: PMC5756666 DOI: 10.1126/sciadv.aao5235] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 11/30/2017] [Indexed: 05/30/2023]
Abstract
The origin of the pseudogap region below a temperature T* is at the heart of the mysteries of cuprate high-temperature superconductors. Unusual properties of the pseudogap phase, such as broken time-reversal and inversion symmetry are observed in several symmetry-sensitive experiments: polarized neutron diffraction, optical birefringence, dichroic angle-resolved photoemission spectroscopy, second harmonic generation, and polar Kerr effect. These properties suggest that the pseudogap region is a genuine thermodynamic phase and are predicted by theories invoking ordered loop currents or other forms of intra-unit-cell (IUC) magnetic order. However, muon spin rotation (μSR) and nuclear magnetic resonance (NMR) experiments do not see the static local fields expected for magnetic order, leaving room for skepticism. The magnetic resonance probes have much longer time scales, however, over which local fields could be averaged by fluctuations. The observable effect of the fluctuations in magnetic resonance is then dynamic relaxation. We have measured dynamic muon spin relaxation rates in single crystals of YBa2Cu3O y (6.72 < y < 6.95) and have discovered "slow" fluctuating magnetic fields with magnitudes and fluctuation rates of the expected orders of magnitude that set in consistently at temperatures Tmag ≈ T*. The absence of any static field (to which μSR would be linearly sensitive) is consistent with the finite correlation length from neutron diffraction. Equally important, these fluctuations exhibit the critical slowing down at Tmag expected near a time-reversal symmetry breaking transition. Our results explain the absence of static magnetism and provide support for the existence of IUC magnetic order in the pseudogap phase.
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Affiliation(s)
- Jian Zhang
- State Key Laboratory of Surface Physics, Department of Physics, Fudan University, Shanghai 200433, People’s Republic of China
| | - Zhaofeng Ding
- State Key Laboratory of Surface Physics, Department of Physics, Fudan University, Shanghai 200433, People’s Republic of China
| | - Cheng Tan
- State Key Laboratory of Surface Physics, Department of Physics, Fudan University, Shanghai 200433, People’s Republic of China
| | - Kevin Huang
- State Key Laboratory of Surface Physics, Department of Physics, Fudan University, Shanghai 200433, People’s Republic of China
| | - Oscar O. Bernal
- Department of Physics and Astronomy, California State University, Los Angeles, CA 90032, USA
| | - Pei-Chun Ho
- Department of Physics, California State University, Fresno, CA 93740, USA
| | | | - Adrian D. Hillier
- ISIS Facility, Science and Technology Facilities Council Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Chilton, Didcot OX11 0QX, UK
| | - Pabitra K. Biswas
- ISIS Facility, Science and Technology Facilities Council Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Chilton, Didcot OX11 0QX, UK
| | - Stephen P. Cottrell
- ISIS Facility, Science and Technology Facilities Council Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Chilton, Didcot OX11 0QX, UK
| | - Hui Xiang
- State Key Lab for Metal Matrix Composites, Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China
| | - Xin Yao
- State Key Lab for Metal Matrix Composites, Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, People’s Republic of China
| | - Douglas E. MacLaughlin
- Department of Physics and Astronomy, University of California, Riverside, Riverside, CA 92521, USA
| | - Lei Shu
- State Key Laboratory of Surface Physics, Department of Physics, Fudan University, Shanghai 200433, People’s Republic of China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, People’s Republic of China
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Movaghar B, Pohlmann B, Schirmacher W. Theory of electronic hopping transport in disordered materials. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/13642818008245369] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- B. Movaghar
- a Fachbereich Physik der Universität Marburg , Renthof 5, D 3550 , Marburg , F.R. Germany
| | - B. Pohlmann
- a Fachbereich Physik der Universität Marburg , Renthof 5, D 3550 , Marburg , F.R. Germany
| | - W. Schirmacher
- a Fachbereich Physik der Universität Marburg , Renthof 5, D 3550 , Marburg , F.R. Germany
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Pratt FL, Blundell SJ, Lancaster T, Baines C, Takagi S. Low-temperature spin diffusion in a highly ideal S=1/2 Heisenberg antiferromagnetic chain studied by muon spin relaxation. PHYSICAL REVIEW LETTERS 2006; 96:247203. [PMID: 16907276 DOI: 10.1103/physrevlett.96.247203] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2006] [Indexed: 05/11/2023]
Abstract
The organic radical-ion salt DEOCC-TCNQF4 contains linear chains of stacked molecules with significant Heisenberg antiferromagnet interactions along the chain and extremely weak interactions between the chains. Zero-field muSR has confirmed the absence of long-range magnetic order down to 20 mK and field-dependent muSR is found to be consistent with diffusive motion of the spin excitations. The anisotropic spin dynamics and the upper boundary for magnetic ordering temperature both indicate interchain magnetic coupling /J'/<7 mK. As the intrachain coupling J is 110 K, /J'/J/ is significantly less than 10(-4). This system therefore provides one of the most ideal examples of the one-dimensional S=1/2 Heisenberg antiferromagnet yet discovered.
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Affiliation(s)
- F L Pratt
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Oxfordshire OX11 0QX, United Kingdom
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Freiländer P, Heitjans P, Ackermann H, Bader B, Kiese G, Schirmer A, Stöckmann HJ, der Marel CV, Magerl A, Zabel H. Diffusion Processes in LiC6 Studied by β-NMR*. ACTA ACUST UNITED AC 1987. [DOI: 10.1524/zpch.1987.151.part_1_2.093] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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