Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


  • NSF Public Access
  • Search Results
  • Colossal magnetoresistance in the multiple wave vector charge density wave regime of an antiferromagnetic Dirac semimetal
Title: Colossal magnetoresistance in the multiple wave vector charge density wave regime of an antiferromagnetic Dirac semimetal
Colossal negative magnetoresistance is a well-known phenomenon, notably observed in hole-doped ferromagnetic manganites. It remains a major research topic due to its potential in technological applications. In contrast, topological semimetals show large but positive magnetoresistance, originated from the high-mobility charge carriers. Here, we show that in the highly electron-doped region, the Dirac semimetal CeSbTe demonstrates similar properties as the manganites. CeSb0.11Te1.90hosts multiple charge density wave modulation vectors and has a complex magnetic phase diagram. We confirm that this compound is an antiferromagnetic Dirac semimetal. Despite having a metallic Fermi surface, the electronic transport properties are semiconductor-like and deviate from known theoretical models. An external magnetic field induces a semiconductor metal–like transition, which results in a colossal negative magnetoresistance. Moreover, signatures of the coupling between the charge density wave and a spin modulation are observed in resistivity. This spin modulation also produces a giant anomalous Hall response.  more » « less
Award ID(s):
2144295
PAR ID:
10475882
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ; ;
Publisher / Repository:
Science Advances
Date Published:
Journal Name:
Science Advances
Volume:
9
Issue:
41
ISSN:
2375-2548
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; ; ; ; ; ; ; et al (, Nature Communications)
    Abstract Contrary to topological insulators, topological semimetals possess a nontrivial chiral anomaly that leads to negative magnetoresistance and are hosts to both conductive bulk states and topological surface states with intriguing transport properties for spintronics. Here, we fabricate highly-ordered metallic Pt3Sn and Pt3SnxFe1-xthin films via sputtering technology. Systematic angular dependence (both in-plane and out-of-plane) study of magnetoresistance presents surprisingly robust quadratic and linear negative longitudinal magnetoresistance features for Pt3Sn and Pt3SnxFe1-x, respectively. We attribute the anomalous negative longitudinal magnetoresistance to the type-II Dirac semimetal phase (pristine Pt3Sn) and/or the formation of tunable Weyl semimetal phases through symmetry breaking processes, such as magnetic-atom doping, as confirmed by first-principles calculations. Furthermore, Pt3Sn and Pt3SnxFe1-xshow the promising performance for facilitating the development of advanced spin-orbit torque devices. These results extend our understanding of chiral anomaly of topological semimetals and can pave the way for exploring novel topological materials for spintronic devices. 
    more » « less
  2. ; ; ; ; ; ; ; (, Optica)
    Terahertz (THz) magnetoresistance effects have been extensively investigated and have shown promising results for applications in magnetic modulations of the amplitude of THz waves. However, THz magnetocapacitance in dielectric systems, which is essential for phase modulations of THz radiation, remains largely unexplored. Here, we study the THz response of a bulk single crystal of La0.875Sr0.125MnO3at around its Curie temperature, observing significant magnetic-field-induced changes in the THz resistance and capacitance extracted from the optical conductivity. We discuss possible mechanisms for the observed coexistence of colossal THz magnetoresistance and magnetocapacitance in a perovskite manganite that is not multiferroic. This work enhances our understanding of colossal magnetoresistance in a complex system with THz spectroscopy and demonstrates potential use of perovskite manganites in THz technology. 
    more » « less
  3. ; ; ; ; ; ; ; ; ; ; et al (, Physical Review B)
    Diluted magnetic semiconductor (DMS) systems have been extensively studied in recent decades. DMSs provides a platform where charge transport and magnetic ordering phenomena exhibit unique interplays, together with possible applications to spin-dependent electronics (spintronics) devices. Initial development of ferromagnetic (FM) DMS systems centered around III-V semiconductors doped with dilute transition metals, such as (Ga,Mn)As, obtained by co-doping of spin and charge. More recently, independent spin and charge doping was first achieved in Li(Zn,Mn)As, a DMS system based on I-II-V semiconductor, with charge doping via variable Li concentrations and spin doping via iso-valent (Zn,Mn) substitutions. Although more than 30 new DMS systems with independent spin and charge doping have been synthesized since then, the main research emphasis has been put on development and characterization of systems with higher FM Curie temperature (TC) and different crystal structures suitable for possible formation of heterostructure devices. This article focuses on a new DMS material Na(Zn,Mn)Sb, which exhibits a spin glass (SG) ordering, together with metal-insulator transition (MIT) and colossal negative magnetoresistance (CMR) as a function of independent spin and charge doping and application of external magnetic fields. MIT and CMR phenomena are elucidated by magneto transport, magnetization, angle resolved photoemission spectroscopy (ARPES), and scanning tunneling microscopy (STM) measurements, and by band calculations which demonstrate development and disappearance of energy gap. Magnetic order and dynamic spin fluctuations are probed with muon spin relaxation (μSR) and magnetization, and the results for Na(Zn,Mn)Sb are compared to those from FM DMS systems Li(Zn,Mn)As, Li(Zn,Mn)P, and Li(Zn,Mn,Cu)As. First-principles calculations are performed for Na(Zn,Mn)Sb, (Ga,Mn)As and Li(Zn,Mn)P to highlight the roles of charge and spin doping on exchange interactions mediated by nearest neighbor super-exchange coupling and oscillatory Ruderman-Kittel-Kasuya-Yosida (RKKY) coupling via conduction electrons. These studies reveal (1) MIT and CMR of Na(Zn,Mn)Sb manifest as a response to spin configurations as spin-driven transport phenomena; (2) a dynamic critical behavior is observed in SG transition of Na(Zn,Mn)Sb, in contrast to more first-order-like magnetic evolutions in other FM DMS systems; (3) charge doping supports FM coupling additive to direct AFM exchange interaction between nearest-neighbor Mn pairs; and (4) a widely different coercive fields seen in different families of FM and SG DMS systems can be explained by geometrical frustration of AFM interaction in underlying lattice for Mn spin network 
    more » « less
  4. ; ; (, Journal of Physics: Condensed Matter)
    Abstract We study magnetotransport in conical helimagnet crystals using the nonequilibriun Boltzmann equation approach. Spin dependent magnetoresistance exhibits dramatic properties for high and low electron concentrations at different temperatures. For spin up electrons we find negative magnetoresistance despite only considering a single carrier type. For spin down electrons we observe giant magnetoresistance due to depletion of spin down electrons with an applied magnetic field. For spin up carriers, the magnetoresistance is negative, due to the increase in charge carriers with a magnetic field. In addition, we investigate the spin dependent Hall effect. If a magnetic field reaches some critical value for spin down electrons, giant Hall resistance occurs, i.e. Hall current vanishes. This effect is explained by the absence of spin down carriers. For spin up carriers, the Hall constant dramatically decreases with field, due to the increase in spin up electron density. Because of the giant spin dependent magnetoresistance and Hall resistivity, conical helimagnets could be useful in spin switching devices. 
    more » « less
  5. (, scholarsphere)
    Abstract: We use a concerted theory-experiment effort to investigate the formation of chiral real space spin texture when the archetypal Dirac semimetal Cd3As2 is interfaced with In1−xMnxAs, a ferromagnetic semiconductor with perpendicular magnetic anisotropy. We combine DFT calculations, the linear response theory for spin susceptibility and micromagnetic simulations to explore the possibility of chiral spin texture in this heterostructure. While a non-zero off-diagonal spin susceptibility in the Cd3As2 layer due to inversion symmetry breaking suggests the presence of Dzyaloshinskii-Moriya interaction (DMI) between local moments in the InMnAs layers, the amplitude may not be strong enough to give a “full” skyrmion texture. Instead, the interace states at the junction may promote a “partial” skyrmion texture. Using electrical magnetoresistance measurements at low temperature, we observe an emergent excess contribution to the transverse magneto-resistance whose behavior is consistent with a topological Hall effect arising from the formation of an interfacial chiral spin texture. This excess Hall voltage varies with gate voltage, indicating a promising electrostatically-tunable platform for understanding the interplay between the helical momentum space states of a Dirac semimetal and chiral real-space spin textures in a ferromagnet. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Text Encoded Conversion
  • XML
  • Save / Share this Record
  • Send to Email