• Kuthanazhi, Brinda
• Schrunk, Benjamin
• Jo, Na Hyun
• Budko, Sergey L.
• Canfield, P. C.
• Orth, Peter P.
• Lee, Kyungchan
• Wu, Yun

Abstract

<jats:title>Abstract</jats:title><jats:p>Electrons navigate more easily in a background of ordered magnetic moments than around randomly oriented ones. This fundamental quantum mechanical principle is due to their Bloch wave nature and also underlies ballistic electronic motion in a perfect crystal. As a result, a paramagnetic metal that develops ferromagnetic order often experiences a sharp drop in the resistivity. Despite the universality of this phenomenon, a direct observation of the impact of ferromagnetic order on the electronic quasiparticles in a magnetic metal is still lacking. Here we demonstrate that quasiparticles experience a significant enhancement of their lifetime in the ferromagnetic state of the low-density magnetic semimetal EuCd<jats:sub>2</jats:sub>As<jats:sub>2</jats:sub>, but this occurs only in selected bands and specific energy ranges. This is a direct consequence of the magnetically induced band splitting and the multi-orbital nature of the material. Our detailed study allows to disentangle different electronic scattering mechanisms due to non-magnetic disorder and magnon exchange. Such high momentum and energy dependence quasiparticle lifetime enhancement can lead to spin selective transport and potential spintronic applications.</jats:p>

Topics

• density
• impedance spectroscopy
• resistivity