Nov. 12, 2015
Effect of Uniaxial Pressure on Structural and Magnetic Phase Transitions in Electron-Doped Iron Pnictides
Space Science Room 106
Space Science and Technology Bldg - Rice University
Houston, Texas 77005
United States
Description
FCMP Lecture (LIVE!)
Date: Thursday, Nov. 12
Time: 3:10 pm
Place: SST 106
Speaker: Prof. Pengcheng Dai, Rice University
Title: Effect of Uniaxial Pressure on Structural and Magnetic Phase Transitions in Electron-Doped Iron Pnictides
Abstract: We use neutron resonance spin echo and Larmor diffraction to study the effect of uniaxial pressure on the tetragonal-to-orthorhombic structural (Ts) and antiferromagnetic (AF) phase transitions in iron pnictides
BaFe2−xNixAs2 (x = 0, 0.03, 0.12), SrFe1.97Ni0.03As2, and BaFe2(As0.7P0.3)2. In antiferromagnetically ordered
BaFe2−xNixAs2 and SrFe1.97Ni0.03As2 with TN and Ts (TN <= Ts), a uniaxial pressure necessary to de-twin the sample also increases TN, smears out the structural transition, and induces an orthorhombic lattice distortion at all temperatures. In addition, the static AF order induces a magnetoelastic distortion of the average lattice d spacing ($\Delta$ d) in the paramagnetic tetragonal phase that decays in the Curie-Weiss fashion and increases with increasing uniaxial pressure. By comparing temperature and doping dependence of the pressure induced lattice parameter changes with the elastoresistance and nematic susceptibility obtained from transport and ultrasonic measurements, we conclude that the in-plane resistivity anisotropy found in the paramagnetic state of electron underdoped iron pnictides depends sensitively on the nature of the magnetic phase transition and a strong coupling between the uniaxial pressure induced lattice distortion and electronic nematic susceptibility.
Date and Time
Thu, Nov. 12, 2015
3:10 p.m. - 4:15 p.m.
(GMT-0500) US/Central
Location
Space Science Room 106
Space Science and Technology Bldg - Rice University
Houston, Texas 77005
United States