skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Band structure evolution during the ultrafast ferromagnetic-paramagnetic phase transition in cobalt

Abstract

The evolution of the electronic band structure of the simple ferromagnets Fe, Co, and Ni during their well-known ferromagnetic-paramagnetic phase transition has been under debate for decades, with no clear and even contradicting experimental observations so far. Using time- and spin-resolved photoelectron spectroscopy, we can make a movie on how the electronic properties change in real time after excitation with an ultrashort laser pulse. This allows us to monitor large transient changes in the spin-resolved electronic band structure of cobalt for the first time. We show that the loss of magnetization is not only found around the Fermi level, where the states are affected by the laser excitation, but also reaches much deeper into the electronic bands. We find that the ferromagnetic-paramagnetic phase transition cannot be explained by a loss of the exchange splitting of the spin-polarized bands but instead shows rapid band mirroring after the excitation, which is a clear signature of extremely efficient ultrafast magnon generation. Our result helps to understand band structure formation in these seemingly simple ferromagnetic systems and gives first clear evidence of the transient processes relevant to femtosecond demagnetization.

Authors:
 [1];  [2];  [1]; ORCiD logo [3];  [4]; ORCiD logo [5]; ORCiD logo [6];  [6];  [2]; ORCiD logo [7];  [3];  [8];  [1]; ORCiD logo [2];  [7]
  1. Univ. of Kaiserslautern and Research Center OPTIMAS, Kaiserslautern (Germany)
  2. Forschungszentrum Julich (Germany). Peter Grunberg Inst. (PGI 6); Experimentalphysik Univ. Duisburg-Essen, Duisburg (Germany)
  3. Univ. of Kaiserslautern and Research Center OPTIMAS, Kaiserslautern (Germany); Graduate School MAINZ, Kaiserslautern (Germany)
  4. Forschungszentrum Julich (Germany). Peter Grunberg Inst. (PGI 6)
  5. Univ. of Colorado, Boulder, CO (United States); National Inst. of Standards and Technology, Boulder, CO (United States). JILA
  6. Univ. of Colorado, Boulder, CO (United States); National Inst. of Standards and Technology, Boulder, CO (United States). JILA
  7. Georg-August-Univ. Gottingen, Gottingen (Germany). I. Physikalisches Inst.
  8. Technische Univ. Dortmund, Dortmund (Germany). Experimentelle Physik VI
Publication Date:
Research Org.:
Univ. of Colorado, Boulder, CO (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division
OSTI Identifier:
1463898
Alternate Identifier(s):
OSTI ID: 1678731
Grant/Contract Number:  
SC0002002
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Science Advances
Additional Journal Information:
Journal Volume: 3; Journal Issue: 3; Journal ID: ISSN 2375-2548
Publisher:
AAAS
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; femtomagnetism; band-structure renormalization; correlated materials; high-harmonic generation; time-resolved photoemission; Stoner vs. Heisenberg picture

Citation Formats

Eich, Steffen, Plötzing, Moritz, Rollinger, Markus, Emmerich, Sebastian, Adam, Roman, Chen, Cong, Kapteyn, Henry Cornelius, Murnane, Margaret M., Plucinski, Lukasz, Steil, Daniel, Stadtmuller, Benjamin, Cinchetti, Mirko, Aeschlimann, Martin, Schneider, Claus M., and Mathias, Stefan. Band structure evolution during the ultrafast ferromagnetic-paramagnetic phase transition in cobalt. United States: N. p., 2017. Web. doi:10.1126/sciadv.1602094.
Eich, Steffen, Plötzing, Moritz, Rollinger, Markus, Emmerich, Sebastian, Adam, Roman, Chen, Cong, Kapteyn, Henry Cornelius, Murnane, Margaret M., Plucinski, Lukasz, Steil, Daniel, Stadtmuller, Benjamin, Cinchetti, Mirko, Aeschlimann, Martin, Schneider, Claus M., & Mathias, Stefan. Band structure evolution during the ultrafast ferromagnetic-paramagnetic phase transition in cobalt. United States. https://doi.org/10.1126/sciadv.1602094
Eich, Steffen, Plötzing, Moritz, Rollinger, Markus, Emmerich, Sebastian, Adam, Roman, Chen, Cong, Kapteyn, Henry Cornelius, Murnane, Margaret M., Plucinski, Lukasz, Steil, Daniel, Stadtmuller, Benjamin, Cinchetti, Mirko, Aeschlimann, Martin, Schneider, Claus M., and Mathias, Stefan. 2017. "Band structure evolution during the ultrafast ferromagnetic-paramagnetic phase transition in cobalt". United States. https://doi.org/10.1126/sciadv.1602094. https://www.osti.gov/servlets/purl/1463898.
@article{osti_1463898,
title = {Band structure evolution during the ultrafast ferromagnetic-paramagnetic phase transition in cobalt},
author = {Eich, Steffen and Plötzing, Moritz and Rollinger, Markus and Emmerich, Sebastian and Adam, Roman and Chen, Cong and Kapteyn, Henry Cornelius and Murnane, Margaret M. and Plucinski, Lukasz and Steil, Daniel and Stadtmuller, Benjamin and Cinchetti, Mirko and Aeschlimann, Martin and Schneider, Claus M. and Mathias, Stefan},
abstractNote = {The evolution of the electronic band structure of the simple ferromagnets Fe, Co, and Ni during their well-known ferromagnetic-paramagnetic phase transition has been under debate for decades, with no clear and even contradicting experimental observations so far. Using time- and spin-resolved photoelectron spectroscopy, we can make a movie on how the electronic properties change in real time after excitation with an ultrashort laser pulse. This allows us to monitor large transient changes in the spin-resolved electronic band structure of cobalt for the first time. We show that the loss of magnetization is not only found around the Fermi level, where the states are affected by the laser excitation, but also reaches much deeper into the electronic bands. We find that the ferromagnetic-paramagnetic phase transition cannot be explained by a loss of the exchange splitting of the spin-polarized bands but instead shows rapid band mirroring after the excitation, which is a clear signature of extremely efficient ultrafast magnon generation. Our result helps to understand band structure formation in these seemingly simple ferromagnetic systems and gives first clear evidence of the transient processes relevant to femtosecond demagnetization.},
doi = {10.1126/sciadv.1602094},
url = {https://www.osti.gov/biblio/1463898}, journal = {Science Advances},
issn = {2375-2548},
number = 3,
volume = 3,
place = {United States},
year = {Fri Mar 24 00:00:00 EDT 2017},
month = {Fri Mar 24 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 83 works
Citation information provided by
Web of Science

Figures / Tables:

Fig. 1 Fig. 1: Schematic of the time- and spin-resolved XUV photoemission spectroscopy experiment and the potential response of the electronic and spin systems to laser-induced demagnetization. (A) The thin, in-plane-magnetized Co film (30 ML) is excited with near-infrared (NIR) laser pulses (74 ± 1 fs, 1.6 eV) that induce demagnetization. Themore » evolution of the band structure is measured via spin- and time-resolved photoemission using XUV pulses (33 ± 7 fs, 22 eV) from high-harmonic generation (HHG). (B) Exchange split density of states for a 3d ferromagnet (left). Reduced magnetization in the Stoner-like picture via a potential collapse of the exchange splitting (middle) and in the localized spin picture via band mirroring (right).« less

Save / Share:

Works referenced in this record:

Driving force of ultrafast magnetization dynamics
journal, December 2011


Spin polarized d surface resonance state of fcc Co/Cu(001)
journal, December 2008


Femtosecond Electron and Spin Dynamics in N i / W ( 110 ) Films
journal, June 2003


Ultrafast magnetization enhancement in metallic multilayers driven by superdiffusive spin current
journal, January 2012


Spin-dependent electronic band structure of Co/Cu(001) with different film thicknesses
journal, April 2008


Time- and angle-resolved photoemission spectroscopy with optimized high-harmonic pulses using frequency-doubled Ti:Sapphire lasers
journal, August 2014


Spin-Polarized Photoemission from f.c.c.-Cobalt above the Curie Temperature: Evidence of Short-Range Magnetic Order
journal, October 1991


Probing the timescale of the exchange interaction in a ferromagnetic alloy
journal, March 2012


Correlation effects and magnetism in 3d transition metals
journal, June 2001


Effects of short-range magnetic order on photoemission and inverse photoemission spectra in iron
journal, March 1985


Superdiffusive Spin Transport as a Mechanism of Ultrafast Demagnetization
journal, July 2010


FERRUM: A New Highly Efficient Spin Detector for Electron Spectroscopy
journal, January 2011


Self-amplified photo-induced gap quenching in a correlated electron material
journal, October 2016


Ultrafast reduction of the total magnetization in iron
journal, January 2014


Ab Initio Investigation of the Elliott-Yafet Electron-Phonon Mechanism in Laser-Induced Ultrafast Demagnetization
journal, November 2011


Explaining the paradoxical diversity of ultrafast laser-induced demagnetization
journal, December 2009


Spin-Orbit Hybridization Points in the Face-Centered-Cubic Cobalt Band Structure
journal, August 2008


Ultrafast spin transport as key to femtosecond demagnetization
journal, January 2013


Spin-resolved photoelectron spectroscopy using femtosecond extreme ultraviolet light pulses from high-order harmonic generation
journal, April 2016


Temperature Dependence of the Exchange Splitting in Ni Studied by Spin-Polarized Photoemission
journal, August 1983


Phase-Matched Generation of Coherent Soft X-rays
journal, May 1998


Ultrafast element-specific magnetization dynamics of complex magnetic materials on a table-top
journal, August 2013


Controlling the Competition between Optically Induced Ultrafast Spin-Flip Scattering and Spin Transport in Magnetic Multilayers
journal, May 2013


Finite-temperature ferromagnetism of nickel
journal, September 1989


Disparate ultrafast dynamics of itinerant and localized magnetic moments in gadolinium metal
journal, September 2015


Super-Diffusive Spin-Transport as a Mechanism of Ultrafast Demagnetization
text, January 2011


Driving Force of Ultrafast Magnetization Dynamics
preprint, January 2011


Self-amplified photo-induced gap quenching in a correlated electron material
journal, October 2016


Ultrafast magnetization enhancement in metallic multilayers driven by superdiffusive spin current
journal, January 2012


Disparate ultrafast dynamics of itinerant and localized magnetic moments in gadolinium metal
journal, September 2015


Explaining the paradoxical diversity of ultrafast laser-induced demagnetization
journal, December 2009


Ultrafast reduction of the total magnetization in iron
journal, January 2014


Probing the timescale of the exchange interaction in a ferromagnetic alloy
journal, March 2012


Spin-dependent electronic band structure of Co/Cu(001) with different film thicknesses
journal, April 2008


Driving force of ultrafast magnetization dynamics
journal, December 2011


Ferromagnetism in the strongly correlated Hubbard model
journal, August 1988


Temperature and wave-vector dependence of the spin-split band structure of Ni(111) along the Γ- L line
journal, December 1990


Correlation effects in the low-energy region of nickel photoemission spectra
journal, April 1999


Transient band structures in the ultrafast demagnetization of ferromagnetic gadolinium and terbium
journal, January 2015


Ultrafast demagnetization of metals: Collapsed exchange versus collective excitations
journal, May 2015


Stoner versus Heisenberg: Ultrafast exchange reduction and magnon generation during laser-induced demagnetization
journal, December 2016


Comparing Ultrafast Demagnetization Rates Between Competing Models for Finite Temperature Magnetism
journal, May 2013


Feedback Effect during Ultrafast Demagnetization Dynamics in Ferromagnets
journal, October 2013


Separating Exchange Splitting from Spin Mixing in Gadolinium by Femtosecond Laser Excitation
journal, November 2015


Local-Band-Theory Analysis of Spin-Polarized, Angle-Resolved Photoemission Spectroscopy
journal, July 1984


Quenching of Majority-Channel Quasiparticle Excitations in Cobalt
journal, May 2002


Phase-Matched Generation of Coherent Soft X-rays
journal, May 1998


Ultrafast and Distinct Spin Dynamics in Magnetic Alloys
journal, September 2015


Super-Diffusive Spin-Transport as a Mechanism of Ultrafast Demagnetization
text, January 2011


Works referencing / citing this record:

Femtosecond X-ray induced changes of the electronic and magnetic response of solids from electron redistribution
journal, November 2019


Spin-orbit torque-mediated spin-wave excitation as an alternative paradigm for femtomagnetism
journal, September 2019


Ultrafast magnetization dynamics in Nickel: impact of pump photon energy
journal, May 2017


Ultrafast demagnetization of Pt magnetic moment in L1 0 -FePt probed by magnetic circular dichroism at a hard x-ray free electron laser
journal, December 2019


Tuning the laser-induced ultrafast demagnetization of transition metals
journal, July 2019


Ab initio theory of magnetization induced by light absorption in ferromagnets
journal, December 2019


Speed and efficiency of femtosecond spin current injection into a nonmagnetic material
journal, September 2017


Magneto-optical probe of ultrafast spin dynamics in antiferromagnetic CoO thin films
journal, October 2018


Broken symmetry states of metallacrowns: Distribution of spins and the g tensor
journal, April 2019


Noise correlations in time- and angle-resolved photoemission spectroscopy
journal, June 2019


Distinctive Picosecond Spin Polarization Dynamics in Bulk Half Metals
journal, August 2018


Early Stages of Ultrafast Spin Dynamics in a 3 d Ferromagnet
journal, August 2018


Ultrafast optically induced spin transfer in ferromagnetic alloys
journal, January 2020


Ultrafast demagnetization in iron: Separating effects by their nonlinearity
text, January 2018


Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.