Nature of the Magnetic Order and Origin of Induced Ferroelectricity in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>TbMnO</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:math>
Physical review letters