Geometrical barriers and lower critical field in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mi>MgB</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>single crystalsL. Lyard, S. I. Lee|Physical Review B|2004Cited by 31