• Bauch, Thilo
• Wahlberg, Eric
• Kalaboukhov, Alexei
• Lombardi, Floriana
• Arpaia, Riccardo

Abstract

<jats:title>Abstract</jats:title><jats:p>We report on measurements of the doping dependence of the upper critical field <jats:inline-formula><jats:tex-math><?CDATA $H_{c,2}$?></jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:msub><mml:mi>H</mml:mi><mml:mrow><mml:mi>c</mml:mi><mml:mo>,</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:math><jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="sustaca93bieqn2.gif" xlink:type="simple" /></jats:inline-formula> in 50 nm thick YBa<jats:sub>2</jats:sub>Cu<jats:sub>3</jats:sub>O<jats:inline-formula><jats:tex-math><?CDATA $_{7-}$?></jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:msub><mml:mi /><mml:mrow><mml:mn>7</mml:mn><mml:mo>−</mml:mo><mml:mi>δ</mml:mi></mml:mrow></mml:msub></mml:math><jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="sustaca93bieqn3.gif" xlink:type="simple" /></jats:inline-formula> films. The films are untwinned and are characterized by a small in-plane compressive strain. We find that the <jats:inline-formula><jats:tex-math><?CDATA $H_{c,2}$?></jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:msub><mml:mi>H</mml:mi><mml:mrow><mml:mi>c</mml:mi><mml:mo>,</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:math><jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="sustaca93bieqn4.gif" xlink:type="simple" /></jats:inline-formula> shows a strong decrease in the underdoped region of the phase diagram, in agreement with that which has been measured in relaxed single crystals. The origin of the decrease of <jats:inline-formula><jats:tex-math><?CDATA $H_{c,2}$?></jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:msub><mml:mi>H</mml:mi><mml:mrow><mml:mi>c</mml:mi><mml:mo>,</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:math><jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="sustaca93bieqn5.gif" xlink:type="simple" /></jats:inline-formula> in the underdoped regime is discussed within a scenario where charge density wave (CDW) order competes with superconductivity. This demonstrates the potential of using thin films to study the phase diagram of high-<jats:italic>T</jats:italic><jats:sub><jats:italic>c</jats:italic></jats:sub> materials under strain, and opens up the possibility for investigating the interplay between CDW order and superconductivity tuned by strain.</jats:p>

Topics

• density
• impedance spectroscopy
• single crystal
• phase
• thin film
• phase diagram
• superconductivity
• superconductivity