Skip to main content

Site navigation

  • University of Technology Sydney home
  • Home

    Home
  • For students

  • For industry

  • Research

Explore

  • Courses
  • Events
  • News
  • Stories
  • People

For you

  • Libraryarrow_right_alt
  • Staffarrow_right_alt
  • Alumniarrow_right_alt
  • Current studentsarrow_right_alt
  • Study at UTS

    • arrow_right_alt Find a course
    • arrow_right_alt Course areas
    • arrow_right_alt Undergraduate students
    • arrow_right_alt Postgraduate students
    • arrow_right_alt Research Masters and PhD
    • arrow_right_alt Online study and short courses
  • Student information

    • arrow_right_alt Current students
    • arrow_right_alt New UTS students
    • arrow_right_alt Graduates (Alumni)
    • arrow_right_alt High school students
    • arrow_right_alt Indigenous students
    • arrow_right_alt International students
  • Admissions

    • arrow_right_alt How to apply
    • arrow_right_alt Entry pathways
    • arrow_right_alt Eligibility
arrow_right_altVisit our hub for students

For you

  • Libraryarrow_right_alt
  • Staffarrow_right_alt
  • Alumniarrow_right_alt
  • Current studentsarrow_right_alt

POPULAR LINKS

  • Apply for a coursearrow_right_alt
  • Current studentsarrow_right_alt
  • Scholarshipsarrow_right_alt
  • Featured industries

    • arrow_right_alt Agriculture and food
    • arrow_right_alt Defence and space
    • arrow_right_alt Energy and transport
    • arrow_right_alt Government and policy
    • arrow_right_alt Health and medical
    • arrow_right_alt Corporate training
  • Explore

    • arrow_right_alt Tech Central
    • arrow_right_alt Case studies
    • arrow_right_alt Research
arrow_right_altVisit our hub for industry

For you

  • Libraryarrow_right_alt
  • Staffarrow_right_alt
  • Alumniarrow_right_alt
  • Current studentsarrow_right_alt

POPULAR LINKS

  • Find a UTS expertarrow_right_alt
  • Partner with usarrow_right_alt
  • Explore

    • arrow_right_alt Explore our research
    • arrow_right_alt Research centres and institutes
    • arrow_right_alt Graduate research
    • arrow_right_alt Research partnerships
arrow_right_altVisit our hub for research

For you

  • Libraryarrow_right_alt
  • Staffarrow_right_alt
  • Alumniarrow_right_alt
  • Current studentsarrow_right_alt

POPULAR LINKS

  • Find a UTS expertarrow_right_alt
  • Research centres and institutesarrow_right_alt
  • University of Technology Sydney home
Explore the University of Technology Sydney
Category Filters:
University of Technology Sydney home University of Technology Sydney home
  1. home
  2. arrow_forward_ios ... Newsroom
  3. arrow_forward_ios ... 2014
  4. arrow_forward_ios 03
  5. arrow_forward_ios Magnetic islands

Magnetic islands

17 March 2014

Discoveries in condensed matter physics are frequently found on the verge of magnetic order at low temperature. Examples include unconventional superconductivity in the high-temperature cuprate and iron pnictide superconductors, the electronic nematic state in Sr3Ru2O7 and the breakdown of the standard theory of metals — Fermi liquid theory — in YbRh2Si2. Because the threshold of magnetism is reached at low temperature by tuning intrinsic material properties rather than by thermal fluctuations, it is called a quantum phase transition or, if the magnetic transition remains second-order, a quantum critical point. The effects of disorder, which are particularly pertinent if magnetism is reached by chemical substitution or doping, are often neglected. Writing in Nature Physics, Soonbeom Seo and collaborators demonstrate that doping-induced disorder can lead to an inhomogeneous magnetic quantum phase transition that is fundamentally distinct from the more commonly explored spatially homogeneous scenario.

Schematic phase diagram of the Ce(Co/Rh)In5 system in zero applied field

Figure 1 | Schematic phase diagram of the Ce(Co/Rh)In5 system in zero applied field. CeRhIn5 is antiferromagnetic at low temperature, but applying pressure or doping with Co drives it into a non-magnetic superconducting state. In contrast, CeCoIn5 is non-magnetic and superconducting, but doping with Rh makes it magnetic. The present study explores whether crossing into the magnetic state from CeCoIn5 by substituting Cd for In works in the same way.

Seo et al. have investigated the superconductor CeCoIn5, which, like a number of related rare-earth-based materials, features ultra-narrow energy bands near the chemical potential. CeCoIn5 and isoelectronic CeRhIn5 are positioned on either side of a magnetic quantum phase transition, enabling detailed studies of quantum criticality and superconductivity in metals (Fig. 1). In the present work, the authors tuned CeCoIn5 across the threshold of magnetism by chemical substitution of In by Cd. An earlier investigation had demonstrated that replacing about 10% of In in CeCoIn5 with Cd induces robust magnetic order at low temperature, which can be removed again by applying hydrostatic pressure. By reducing Cd doping levels tenfold, the present study homes in on the immediate vicinity of the quantum phase transition. The latest results suggest that even 1% Cd doping is sufficient to induce magnetic order in CeCoIn5, but that the magnetic transition has an unexpected character: at low temperature Cd impurities nucleate magnetic regions, which are separated by pristine CeCoIn5, leading to a highly inhomogeneous magnetic state when the Cd concentration is low.

Two routes illustrating how to induce magnetism in metals

Figure 2 | Routes to induce magnetism in metals. Upper panel: Illustrating the magnetic ordering temperature Tm as elevation above sea level. Non-magnetic material corresponds to submerged areas, whereas high magnetic-ordering temperatures correspond to mountain ranges. The critical point occurs when Tm goes to zero smoothly. This can be achieved by tuning the material composition or by changing external parameters such as pressure or magnetic field. The fertile ‘mudflats’ close to the critical point give rise to numerous interesting correlated states in narrow-band metals. Lower panel: Seo et al. argue that Cd impurities in CeCoIn5 nucleate spatially confined magnetic regions, analogous to volcanic islands rising from the deep sea. The magnetic correlation length ξ sets the length scale over which Tm can vary and thereby defines the island size. Long-range magnetic order sets in if the correlation length exceeds the distance between the Cd atoms.

Figure 2 illustrates the fundamental difference between the conventional tuning approach and the mechanism put forward by Seo et al. as operating in Cd-doped CeCoIn5. The magnetic ordering temperature Tm varies over intermediate length-scales, and is analogous to the elevation of a land mass compared with sea level. CeCoIn5 corresponds to a flat land mass just submerged, whereas CeRhIn5 can be pictured as a highland plateau. By changing the water level, corresponding to applying pressure or varying the ratio of Co to Rh, one can be tuned into the other. Substitution of In by Cd in CeCoIn5, however, locally elevates Tm over a tightly defined region around each Cd site, creating the analogue of a volcanic island. The resulting heterogeneous material will not necessarily develop long-range magnetic order, but this will occur eventually if the separation between the islands becomes less than their size.

Byline

F. Malte Grosche
Share
Share this on Facebook Share this on Twitter Share this on LinkedIn
Back to News in Materials and Technology for Energy Efficiency

Acknowledgement of Country

UTS acknowledges the Gadigal People of the Eora Nation and the Boorooberongal People of the Dharug Nation upon whose ancestral lands our campuses now stand. We would also like to pay respect to the Elders both past and present, acknowledging them as the traditional custodians of knowledge for these lands. 

University of Technology Sydney

City Campus

15 Broadway, Ultimo, NSW 2007

Get in touch with UTS

Follow us

  • Instagram
  • LinkedIn
  • YouTube
  • Facebook

A member of

  • Australian Technology Network
Use arrow keys to navigate within each column of links. Press Tab to move between columns.

Study

  • Find a course
  • Undergraduate
  • Postgraduate
  • How to apply
  • Scholarships and prizes
  • International students
  • Campus maps
  • Accommodation

Engage

  • Find an expert
  • Industry
  • News
  • Events
  • Experience UTS
  • Research
  • Stories
  • Alumni

About

  • Who we are
  • Faculties
  • Learning and teaching
  • Sustainability
  • Initiatives
  • Equity, diversity and inclusion
  • Campus and locations
  • Awards and rankings
  • UTS governance

Staff and students

  • Current students
  • Help and support
  • Library
  • Policies
  • StaffConnect
  • Working at UTS
  • UTS Handbook
  • Contact us
  • Copyright © 2025
  • ABN: 77 257 686 961
  • CRICOS provider number: 00099F
  • TEQSA provider number: PRV12060
  • TEQSA category: Australian University
  • Privacy
  • Copyright
  • Disclaimer
  • Accessibility