Pressure Induced Quantum Phase Transitions

Abstract

A quantum critical point is approached by applying pressure in a number of magnetic metals. The observed dependence of Tc on pressure necessarily means that the magnetic energy is coupled to the lattice. A first order phase transition occurs if this coupling exceeds a critical value: this is inevitable if diverges as Tc approaches zero. It is argued that this is the cause of the first order transition that is observed in many systems. Using Landau theory we obtain expressions for the boundaries of the region where phase separation occurs that agree well with experiments done on MnSi and other materials. The theory can be used to obtain very approximate values for the temperature and pressure at the tricritical point in terms of quantities measured at ambient pressure and the measured values of along the second order line. The values of the tricritical temperature for various materials obtained from Landau theory are too low but it is shown that the predicted values will rise if the effects of fluctuations are included.

12 pages including figures

References in corpus (12)

• First order transitions and multicritical points in weak itinerant ferromagnets
• Quantum Phase Transitions in the Itinerant Ferromagnet ZrZn${}_2$
• Pressure dependence of the magnetization in the ferromagnetic superconductor UGe_2
• Metamagnetic Quantum Criticality
• Phase separation and suppression of critical dynamics at quantum transitions of itinerant magnets: MnSi and (Sr${}_{1-x}$Ca${}_x$)RuO${}_3$
• Ferromagnetic superconductivity driven by changing Fermi surface topology
• Ferromagnetic Properties of ZrZn${}_2$
• Phase Inhomogeneity of the Itinerant Ferromagnet MnSi at High Pressures
• Critical Phenomena and the Quantum Critical Point of Ferromagnetic Zr1-xNbxZn2
• Infrared and optical spectroscopy of alpha and gamma-phase Ce
• Unconventional Superconductivity in Heavy Fermion Systems
• Tricritical behavior in MnSi at nearly hydrostatic pressure

Cited by in corpus (14)

• Metallic Quantum Ferromagnets
• Review of U-based Ferromagnetic Superconductors: Comparison between UGe2, URhGe, and UCoGe
• Tricritical point and wing structure in the itinerant ferromagnet UGe2
• Unconventional critical scaling of magnetization in uranium ferromagnetic superconductors UGe${}_2$ and URhGe
• Disorder dependence of the ferromagnetic quantum phase transition
• Unconventional Strong Spin-Fluctuation Effects around the Critical Pressure of the Itinerant Ising-Type Ferromagnet URhAl
• Thermodynamics of ferromagnetic superconductors with spin-triplet electron pairing
• Quantum Annealed Criticality
• Quantum Annealed Criticality: A Scaling Description
• Thermodynamic model of a solid with RKKY interaction and magnetoelastic coupling
• Self-consistent model of a solid for the description of lattice and magnetic properties
• Fluctuations and Criticality in Quantum Paraelectrics
• Prediction of magnetic moment collapse in ZrFe${}_2$ under hydrostatic pressure
• Landau theory of compressible magnets near a quantum critical point