St Andrews Research Repository

St Andrews University Home
View Item 
  •   St Andrews Research Repository
  • Physics & Astronomy (School of)
  • Physics & Astronomy
  • Physics & Astronomy Theses
  • View Item
  •   St Andrews Research Repository
  • Physics & Astronomy (School of)
  • Physics & Astronomy
  • Physics & Astronomy Theses
  • View Item
  •   St Andrews Research Repository
  • Physics & Astronomy (School of)
  • Physics & Astronomy
  • Physics & Astronomy Theses
  • View Item
  • Login
JavaScript is disabled for your browser. Some features of this site may not work without it.

Magnetothermal properties near quantum criticality in the itinerant metamagnet Sr₃Ru₂O₇

Thumbnail
View/Open
AndreasRostPhDThesis.pdf (7.827Mb)
Date
26/06/2009
Author
Rost, Andreas W.
Supervisor
Mackenzie, Andrew
Grigera, Santiago A.
Funder
SUPA Graduate School
Engineering and Physical Sciences Research Council (EPSRC)
Keywords
Physics
Condensed matter
Specific heat
Magnetocaloric effect
Quantum criticality
Sr₃Ru₂O₇
Strongly correlated electron systems
Metadata
Show full item record
Altmetrics Handle Statistics
Abstract
The search for novel quantum states is a fundamental theme in condensed matter physics. The almost boundless number of possible materials and complexity of the theory of electrons in solids make this both an experimentally and theoretically exciting and challenging research field. Particularly, the concept of quantum criticality resulted in a range of discoveries of novel quantum phases, which can become thermodynamically stable in the vicinity of a second order phase transition at zero temperature due to the existence of quantum critical fluctuations. One of the materials in which a novel quantum phase is believed to form close to a proposed quantum critical point is Sr₃Ru₂O₇. In this quasi-two-dimensional metal, the critical end point of a line of metamagnetic first order phase transitions can be suppressed towards zero temperature, theoretically leading to a quantum critical end point. Before reaching absolute zero, one experimentally observes the formation of an anomalous phase region, which has unusual ‘nematic-like’ transport properties. In this thesis magnetocaloric effect and specific heat measurements are used to systematically study the entropy of Sr₃Ru₂O₇ as a function of both magnetic field and temperature. It is shown that the boundaries of the anomalous phase region are consistent with true thermodynamic equilibrium phase transitions, separating the novel quantum phase from the surrounding ‘normal’ states. The anomalous phase is found to have a higher entropy than the low and high field states as well as a temperature dependence of the specific heat which deviates from standard Fermi liquid predictions. Furthermore, it is shown that the entropy in the surrounding ‘normal’ states increases significantly towards the metamagnetic region. In combination with data from other experiments it is concluded that these changes in entropy are most likely caused by many body effects related to the underlying quantum phase transition.
Type
Thesis, PhD Doctor of Philosophy
Collections
  • Physics & Astronomy Theses
URI
http://hdl.handle.net/10023/837

Items in the St Andrews Research Repository are protected by copyright, with all rights reserved, unless otherwise indicated.

Advanced Search

Browse

All of RepositoryCommunities & CollectionsBy Issue DateNamesTitlesSubjectsClassificationTypeFunderThis CollectionBy Issue DateNamesTitlesSubjectsClassificationTypeFunder

My Account

Login

Open Access

To find out how you can benefit from open access to research, see our library web pages and Open Access blog. For open access help contact: openaccess@st-andrews.ac.uk.

Accessibility

Read our Accessibility statement.

How to submit research papers

The full text of research papers can be submitted to the repository via Pure, the University's research information system. For help see our guide: How to deposit in Pure.

Electronic thesis deposit

Help with deposit.

Repository help

For repository help contact: Digital-Repository@st-andrews.ac.uk.

Give Feedback

Cookie policy

This site may use cookies. Please see Terms and Conditions.

Usage statistics

COUNTER-compliant statistics on downloads from the repository are available from the IRUS-UK Service. Contact us for information.

© University of St Andrews Library

University of St Andrews is a charity registered in Scotland, No SC013532.

  • Facebook
  • Twitter