Magnetic microscopy. Real-space imaging of the atomic-scale magnetic structure of Fe(1+y)Te.

Enayat, Mostafa; Sun, Zhixiang; Singh, Udai Raj; Aluru, Ramakrishna; Schmaus, Stefan; Yaresko, Alexander; Liu, Yong; Lin, Chengtian et al. · Science · 2014

basic_science · Level V

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Abstract

Spin-polarized scanning tunneling microscopy (SP-STM) has been used extensively to study magnetic properties of nanostructures. Using SP-STM to visualize magnetic order in strongly correlated materials on an atomic scale is highly desirable, but challenging. We achieved this goal in iron tellurium (Fe(1+ y)Te), the nonsuperconducting parent compound of the iron chalcogenides, by using a STM tip with a magnetic cluster at its apex. Our images of the magnetic structure reveal that the magnetic order in the monoclinic phase is a unidirectional stripe order; in the orthorhombic phase at higher excess iron concentration (y > 0.12), a transition to a phase with coexisting magnetic orders in both directions is observed. It may be possible to generalize the technique to other high-temperature superconductor families, such as the cuprates.