Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2016 Nov 24:7:13406.
doi: 10.1038/ncomms13406.

Optically switched magnetism in photovoltaic perovskite CH3NH3(Mn:Pb)I3

B Náfrádi  1 , P Szirmai  1 , M Spina  1 , H Lee  2 , O V Yazyev  2 , A Arakcheeva  1 , D Chernyshov  3 , M Gibert  4 , L Forró  1 , E Horváth  1
Affiliations

Optically switched magnetism in photovoltaic perovskite CH3NH3(Mn:Pb)I3

B Náfrádi et al. Nat Commun. .

Abstract

The demand for ever-increasing density of information storage and speed of manipulation boosts an intense search for new magnetic materials and novel ways of controlling the magnetic bit. Here, we report the synthesis of a ferromagnetic photovoltaic CH3NH3(Mn:Pb)I3 material in which the photo-excited electrons rapidly melt the local magnetic order through the Ruderman-Kittel-Kasuya-Yosida interactions without heating up the spin system. Our finding offers an alternative, very simple and efficient way of optical spin control, and opens an avenue for applications in low-power, light controlling magnetic devices.

PubMed Disclaimer

Figures

Figure 1
Figure 1. Sample and measurement configuration.
(a) Photo of a typical CH3NH3(Mn:Pb)I3 crystal, 10–15 were assembled for the ESR measurement. (b) Sketch of the crystal structure of CH3NH3(Mn:Pb)I3. (c) The experimental configuration for the high-field ESR measurements showing the assembly of small crystals (sample). The absorption of the microwave field provided by the microwave source (MW source, up to 315 GHz) is monitored (MW detector) in resonant conditions in dark and under illumination in reflection geometry (MW mirror). The light source is a red (λ=655 nm, 4 μW cm−2) LED activated by an external switch (switch).
Figure 2
Figure 2. Magnetic properties of CH3NH3(Mn:Pb)I3 in dark.
(a) ESR linewidth (red dots) and resonant field (blue dots, offset by a reference value B0) as a function of temperature recorded at 9.4 GHz. Their temperature-independent behaviour is characteristic for the paramagnetic phase (PM). The upturn below 25 K corresponds to the on-set of the FM phase. Inset: SQUID magnetometry of MAMn:PbI3. The temperature dependence of the spontaneous magnetization measured in 1.2 μT magnetic field shows a clear increase below TC. The red line represents the M0(1−(T/TC)3/2) temperature dependence given by Bloch's Law. (b) First-principles calculations of the atomic configurations and magnetic order show total density of states (DOS) and projected density of states (PDOS) calculated for the in-plane model of CH3NH3(Mn:Pb)I3 in its neutral FM configuration. (c) Calculated Pb–I and Mn–I distances for a single Mn dopant. (d) Calculated bond angles and bond distances for the I mediated super-exchange paths in the FM ground state of the in-plane model of CH3NH3(Mn:Pb)I3.
Figure 3
Figure 3. Illumination effect on the magnetic properties of CH3NH3(Mn:Pb)I3 measured by ESR.
(a) The intensity change as the function of the illuminating red light intensity Φ at T=5 K. Above a threshold value, the FM part of the signal decreases monotonously. (b) Light-on ESR linewidth normalized to the linewidth in dark. The narrowing of the linewidth on illumination starts below TC. (c) ESR spectra at 157 GHz and 5 K of pristine CH3NH3PbI3 (green line–no signal), of CH3NH3(Mn:Pb)I3 in dark (blue line) coming from the FM phase and its reduction (red line) on visible light illumination. The difference between light-off and light-on ESR signals is shown in orange. The effect is accompanied by narrowing of the ESR linewidth on illumination. (d) Difference of the ESR intensities between the light-off and light-on measurements as a function of temperature. (The third axis shows the resonant field of the signal.) The intensity reduction on illumination is present only below TC=25 K, in the FM phase. Error bars represent the confidence interval of least square fits to the spectra.
Figure 4
Figure 4. Schematic illustration of writing a magnetic bit.
In the dark (a) the spin alignment corresponds to a given orientation of the magnetic moment in the FM state, representing a bit. On illumination (b) the FM order melts and a small magnetic field of the writing head will set the orientation of the magnetic moment once the light is switched off (c).
See this image and copyright information in PMC

References

    1. Hwang H., Palstra T., Cheong S. & Batlogg B. Pressure effects on the magnetoresistance in doped manganese perovskites. Phys. Rev. B 52, 15046–15049 (1995). - PubMed
    1. Snively L. O., Tuthill G. F. & Drumheller J. E. Measurement and calculation of the superexchange interaction through the two-halide bridge in the eclipsed layered compounds [NH3(CH2)nNH3]CuX for n=2–5 and X=Cl4 and Cl2Br2. Phys. Rev. B 24, 5349–5355 (1981).
    1. Kimel A. V., Kirilyuk A., Tsvetkov A., Pisarev R. V. & Rasing T. Laser-induced ultrafast spin reorientation in the antiferromagnet TmFeO3. Nature 429, 850–853 (2004). - PubMed
    1. Ohno H. et al. Electric-field control of ferromagnetism. Nature 408, 944–946 (2000). - PubMed
    1. Lottermoser T. et al. Magnetic phase control by an electric field. Nature 430, 541–544 (2004). - PubMed

Publication types