Magnetic Gold; Structure Dependent Ferromagnetism in Au4V

Structure-dependent ferromagnetism in Au 4 V studied under high pressure Investigations into Magnetic Gold D. D. Jackson et al. , PRB 74 , 174401, 2006 This work was performed under the auspices of the U.S. Department of Energy by University of California, Lawrence Livermore National Laboratory under Contract W-7405-Eng-48. Lawrence Livermore National Laboratory University of California Livermore, CA 94550 Damon D Jackson Chantel Aracne Sam T. Weir Wei Qiu Joel D. Griffith Yogesh Vohra University of Alabama at Birmingham Department of Physics Birmingham, AL 35294 Jason Jeffries * Brian Maple University of California, San Diego Department of Physics San Diego, CA 92093 * Now at LLNL

Overview ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Magnetic Phase Diagram Au 4 V Au - 20% V

Electrical Resistivity of Metals

Electrical Resistivity vs Temperature for Metals ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],ρ( T )=ρ 0 +ρ electrons ( T )+ρ phonons ( T ) ρ( T )=ρ 0 + a T 2 + b T 5 + c T Typical Metallic Behavior

Good Metals with Magnetic Impurities ,[object Object],[object Object],[object Object],[object Object],Magnetic Impurities cause ρ( T )to increase at low T Jun Kondo, Prog. Theor. Phys. 32 , 37, 1964

Kondo Effect ,[object Object],[object Object],[object Object]

Kondo Effect ,[object Object],[object Object],[object Object],Ziman, “Electrons and Phonons”

Kondo’s Theory of the Resistance Minima ,[object Object],[object Object],[object Object],[object Object],[object Object],Kondo Resistance Schilling, Adv. Phys. 28 , 657, 1979 T K ≈ T F exp(-1/| J N ( E F ) | ) ρ spin ( T )=Δρ( T )=ρ imp ( T ) - ρ host ( T ) Jun Kondo, Prog. Theor. Phys. 32 , 37, 1964

Kondo’s Theory of the Resistance Minima ,[object Object],[object Object],[object Object],[object Object],[object Object],Example ρ( T ) for Various T K Schilling, Adv. Phys. 28 , 657, 1979 T K ≈ T F exp(-1/| J N ( E F ) | ) ρ spin ( T )=Δρ( T )=ρ imp ( T ) - ρ host ( T ) Jun Kondo, Prog. Theor. Phys. 32 , 37, 1964

Kondo Under Pressure ,[object Object],[object Object],[object Object],[object Object],Schilling, Adv. Phys. 28 , 657, 1979 T K ≈ T F exp(-1/| J N ( E F ) | ) Kondo Resistance with Pressure

Kondo Under Pressure ,[object Object],[object Object],[object Object],[object Object],Magnetic Exchange with Pressure Schilling, Adv. Phys. 28 , 657, 1979 T K ≈ T F exp(-1/| J N ( E F ) | )

Electrical Resistivity of Au-V Alloys

Electrical Resistivity of Au-V Alloys ,[object Object],[object Object],[object Object],Au-V Resistance Kondo Resistance ρ spin ( T )=Δρ( T )=ρ Au-V ( T ) - ρ Au ( T )

Kondo Behavior in Au-V Alloys ,[object Object],[object Object],[object Object],[object Object],[object Object]

Kondo Behavior in Au-V Alloys ,[object Object],[object Object],[object Object],[object Object],[object Object],dT K /d P ≈ 6.5 K/GPa

Au-V Kondo Behavior Review ,[object Object],[object Object],[object Object],[object Object],[object Object]

Au-V Kondo Behavior Review ,[object Object],[object Object],[object Object],[object Object],[object Object],Ziman, “Electrons and Phonons”

Au-V Kondo Behavior Review ,[object Object],[object Object],[object Object],[object Object],[object Object],Schilling, Adv. Phys. 28 , 657, 1979

Au-V Kondo Behavior Review ,[object Object],[object Object],[object Object],[object Object],[object Object],T K vs P for Au-0.5%V

Discovery of Ferromagnetism in Ordered Au 4 V ,[object Object],[object Object],[object Object],[object Object],[object Object],L. Creveling et al., Phys Rev. Lett., 18 , 851 (1967)

Discovery of Ferromagnetism in Ordered Au 4 V ,[object Object],[object Object],[object Object],[object Object],[object Object],Magnetization of Au 4 V L. Creveling et al., Phys Rev. Lett., 18 , 851 (1967)

Discovery of Ferromagnetism in Ordered Au 4 V ,[object Object],[object Object],[object Object],[object Object],[object Object],Curie-Weiss behavior of Au 4 V L. Creveling et al., Phys Rev. Lett., 18 , 851 (1967)

Crystal Structure ,[object Object],[object Object],[object Object],[object Object],[object Object],• Gold crystal structure is the basis for Au-V alloys • fcc (F m-3m ) • a=4.08 Å

X-Ray Analysis ,[object Object],[object Object],[object Object],[object Object],Angle Dispersive XRD Energy Dispersive XRD

EOS for Au 4 V ,[object Object],[object Object],[object Object],[object Object],[object Object],Au 4 V EOS

[object Object],[object Object],[object Object],Diamond Anvil Cell: The tool for ultra-high pressure research DAC capabilities are limited for electrical transport, magnetic properties, etc.

Designer Diamond Anvils ,[object Object],[object Object],[object Object],[object Object],60-250 µm 4-12 µm

[object Object],[object Object],[object Object],[object Object],1st Step: Lithography onto Diamond Anvils Electrical Contact Pads

[object Object],[object Object],[object Object],2nd Step: Microwave Plasma Chemical Vapor Deposition Yogesh Vohra, Univ. of Alabama, Birmingham Plasma Heated Substrate (1000 C) Diamond Growth H 2 CH 4 Microwave Power

[object Object],3rd Step: Polishing rate of diamond nucleation and growth on clean metal films is low electrical contact pads

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Designer Diamond Anvil Fabrication 300 µm

Broad Range of Techniques 300 µm I I I I I I V Heating element in operation at ≈10 GPa Electrical Resistivity Magnetic Susceptibility Internal Ohmic Heating 10  m

Electrical Resistance of Au 4 V ,[object Object],[object Object],[object Object],M.B. Maple et al., Phys. Lett. A, 25 , 121 (1967)

Au 4 V Resistivity Under Pressure ,[object Object],[object Object],[object Object],[object Object],[object Object],G.Y. Chin et al., Solid State Comm., 6 , 153 (1968)

T C vs Pressure Phase Diagram ,[object Object],[object Object],[object Object],[object Object],[object Object],Magnetic Phase Diagram

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Review of Experimental Results

Theoretical Description of Au 4 V Ferromagnetism

Kondo Coupling ⇔ T C increase ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],✓ ✓ ✓ ≈ -1.8 d ln T K /d ln V ≈ -7

Kondo Coupling ⇔ T C increase ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],✓ ✓ ✓ ✓ ≈ -1.8 ≈ -5.3 d ln T K /d ln V ≈ -7 d ln T C /d ln V ≈ -9.9 ?

Structure and Magnetism ,[object Object],[object Object],[object Object],[object Object],[object Object]

Magnetic Nearest Neighbors ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Must Account for Structure Changes d ln z /d ln V ≈ -7 d ln T K /d ln V ≈ -7 d ln T C /d ln V ≈ -9.9 d ln| J|/d ln V ≈ -1.8 ℐ ∝ N ( E F ) J 2 Au-0.5%V Au 4 V

Must Account for Structure Changes ,[object Object],[object Object],[object Object],d ln| J|/d ln V ≈ -1.8 d ln z /d ln V ≈ -7 d ln T C /d ln V ≈ -9.9 Au 4 V • P ( z =3.6) = 21 GPa

Must Account for Structure Changes ,[object Object],[object Object],[object Object],Au 4 V Phase Diagram • P ( z =3.6) = 21 GPa

Structure- Dependent Ferromagnetism in Au 4 V

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Structure-dependent ferromagnetism in Au 4 V studied under high pressure Au-.5%V Kondo Behavior

Structure-dependent ferromagnetism in Au 4 V studied under high pressure ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],T K vs P for Au-0.5%V

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Structure-dependent ferromagnetism in Au 4 V studied under high pressure Au 4 V Crystal Structure

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Structure-dependent ferromagnetism in Au 4 V studied under high pressure bct to fcc Transformation

Structure-dependent ferromagnetism in Au 4 V studied under high pressure ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Magnetic Phase Diagram

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Structure-dependent ferromagnetism in Au 4 V studied under high pressure Au 4 V Phase Diagram Au 4 V Au - 20% V

Discovery of Ferromagnetism in Ordered Au 4 V ,[object Object],[object Object],[object Object],[object Object],L. Creveling et al., Phys Rev. Lett., 18 , 851 (1967) G.Y. Chin et al., Solid St. Comm., 6 , 153 (1968) High T suggests local moment picture ( S =1/2) and low T suggests itinerant ferromagnetic picture

S =1/2 moment at V site ,[object Object],[object Object],[object Object],[object Object],H.L. Luo et al., Phys. Lett. A, 28 , 740 (1967) R.L. Cohen et al., Phys. Rev., 188 , 684 (1969) G. Kido et al., J. Magn. Magn. Mater., 31-34 , 283 (1983) V has S =1/2 local moment as long as nearest neighbors are Au

[object Object],[object Object],[object Object],Designer Diamond Anvils D.D. Jackson et al., Rev. Sci. Instrum., 74 , 2467 (2003) diamond-encapsulated probes remain functional to multi-Mbar pressures

Designer Diamond Anvils for Electrical Resistivity ,[object Object],[object Object],[object Object],[object Object]

Kondo’s Solution ,[object Object],[object Object],Jun Kondo, Prog. Theor. Phys. 32 , 37, 1964

Kondo’s Solution ,[object Object],[object Object],Jun Kondo, Prog. Theor. Phys. 32 , 37, 1964 Exchange Interaction

Kondo’s Solution ,[object Object],[object Object],Jun Kondo, Prog. Theor. Phys. 32 , 37, 1964 Spin due to the Magnetic Impurity

Kondo’s Solution ,[object Object],[object Object],Jun Kondo, Prog. Theor. Phys. 32 , 37, 1964 Spin Density of Host Metal Conduction Electrons

Kondo’s Solution ,[object Object],[object Object],Jun Kondo, Prog. Theor. Phys. 32 , 37, 1964 Scattering Potential

Magnetic Gold; Structure Dependent Ferromagnetism in Au4V

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Magnetic Gold; Structure Dependent Ferromagnetism in Au4V