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ABSTRACT Organic semiconductors are studied intensively for applications in electronics and optics1, and even spin-based information technology, or spintronics2. Fundamental quantities in

spintronics are the population relaxation time (_T_1) and the phase memory time (_T_2): _T_1 measures the lifetime of a classical bit, in this case embodied by a spin oriented either

parallel or antiparallel to an external magnetic field, and _T_2 measures the corresponding lifetime of a quantum bit, encoded in the phase of the quantum state. Here we establish that these

times are surprisingly long for a common, low-cost and chemically modifiable organic semiconductor, the blue pigment copper phthalocyanine3, in easily processed thin-film form of the type

used for device fabrication. At 5 K, a temperature reachable using inexpensive closed-cycle refrigerators, _T_1 and _T_2 are respectively 59 ms and 2.6 μs, and at 80 K, which is just above

the boiling point of liquid nitrogen, they are respectively 10 μs and 1 μs, demonstrating that the performance of thin-film copper phthalocyanine is superior to that of single-molecule

magnets over the same temperature range4. _T_2 is more than two orders of magnitude greater than the duration of the spin manipulation pulses, which suggests that copper phthalocyanine holds

promise for quantum information processing, and the long _T_1 indicates possibilities for medium-term storage of classical bits in all-organic devices on plastic substrates. Access through

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BEING VIEWED BY OTHERS CONTROLLING THE HELICITY OF LIGHT BY ELECTRICAL MAGNETIZATION SWITCHING Article 27 March 2024 QUANTUM MATERIALS FOR SPINTRONIC APPLICATIONS Article Open access 25 July

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S.H. and Z.W. thank EPSRC (EP/F039948/1) for the award of a First Grant. S.H. and S.D. thank Kurt J. Lesker and EPSRC for a CASE award. Work at UCL and Imperial College was supported by the

EPSRC Basic Technologies grant Molecular Spintronics (EP/F041349/1 and EP/F04139X/1). G.W.M. is supported by the Royal Society. I.S.T. thanks IARPA, NSERC (grant CNXP 22R81695) and PITP for

support. AUTHOR INFORMATION Author notes * Marc Warner, Gavin W. Morley & Jules A. Gardener Present address: Present addresses: Department of Physics, Harvard University, Cambridge,

Massachusetts 02138, USA (M.W.); Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK (G.W.M.); RMD Inc., 44 Hunt Street, Watertown, Massachusetts 02472, USA

(J.A.G.)., * A. Marshall Stoneham: Deceased. AUTHORS AND AFFILIATIONS * London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London WC1H 0AH,

UK, Marc Warner, Gavin W. Morley, A. Marshall Stoneham, Jules A. Gardener, Andrew J. Fisher & Gabriel Aeppli * London Centre for Nanotechnology and Department of Materials, Imperial

College London, London SW7 2AZ, UK, Salahud Din, Zhenlin Wu & Sandrine Heutz * Pacific Institute of Theoretical Physics, University of British Columbia, Vancouver, British Columbia V6T

1Z1, Canada, Igor S. Tupitsyn * Institute of Structural & Molecular Biology and London Centre for Nanotechnology, University College London, London WC1E 6BT, UK, Christopher W. M. Kay

Authors * Marc Warner View author publications You can also search for this author inPubMed Google Scholar * Salahud Din View author publications You can also search for this author inPubMed

 Google Scholar * Igor S. Tupitsyn View author publications You can also search for this author inPubMed Google Scholar * Gavin W. Morley View author publications You can also search for

this author inPubMed Google Scholar * A. Marshall Stoneham View author publications You can also search for this author inPubMed Google Scholar * Jules A. Gardener View author publications

You can also search for this author inPubMed Google Scholar * Zhenlin Wu View author publications You can also search for this author inPubMed Google Scholar * Andrew J. Fisher View author

publications You can also search for this author inPubMed Google Scholar * Sandrine Heutz View author publications You can also search for this author inPubMed Google Scholar * Christopher

W. M. Kay View author publications You can also search for this author inPubMed Google Scholar * Gabriel Aeppli View author publications You can also search for this author inPubMed Google

Scholar CONTRIBUTIONS M.W. conducted the electron spin resonance measurements with input and supervision from G.A. and C.W.M.K. S.D., J.A.G. and Z.W. made and characterized the samples with

input and supervision from S.H.. M.W., G.W.M., A.M.S., A.J.F., C.W.M.K. and G.A. analysed data, I.S.T. performed theoretical work, and M.W. wrote the manuscript. CORRESPONDING AUTHORS

Correspondence to Marc Warner or Gabriel Aeppli. ETHICS DECLARATIONS COMPETING INTERESTS The authors declare no competing financial interests. EXTENDED DATA FIGURES AND TABLES EXTENDED DATA

FIGURE 1 STRETCHED-EXPONENTIAL _T_1 FITS. Inversion recovery echoes for varying CuPc concentrations fitted with stretched exponentials. The _T_1 decay of each echo magnitude can also be

fitted to a stretched exponential, _A_exp(−_x_/_k_)_β_, which is a form characteristic of the random environment that the CuPc molecules experience. In particular, the more isolated

molecules will show slower relaxation34. However, because the stretched exponential is a phenomenological fit, it must be interpreted with care, particularly in cases where the underlying

distribution of relaxation times is highly non-trivial. This is the case in this work, where relaxation times depend strongly on long-range dipolar interactions and, therefore, the finite

size of the crystallites35. EXTENDED DATA FIGURE 2 DECAY TIMES OF STRETCHED-EXPONENTIAL FITS. Decay times extracted from the fits in Extended Data Fig. 1 and plotted against CuPc

concentration. The concentration dependence of _T_1 is not greatly affected by the change in fit. This allows the interpretation of the data based on the simpler mono-exponential fits (main

text). EXTENDED DATA FIGURE 3 POWER-LAW EXPONENTS OF STRETCHED-EXPONENTIAL FITS. Magnitudes of the power-law exponent, _β_, in the fits in Extended Data Fig. 2 plotted against CuPc

concentration. In a uniform environment, _β_ = 1 for the population of spins. The greater is the deviation from this value, the larger is the proportion of long-lived isolated spins relative

to the average. POWERPOINT SLIDES POWERPOINT SLIDE FOR FIG. 1 POWERPOINT SLIDE FOR FIG. 2 POWERPOINT SLIDE FOR FIG. 3 POWERPOINT SLIDE FOR FIG. 4 RIGHTS AND PERMISSIONS Reprints and

permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Warner, M., Din, S., Tupitsyn, I. _et al._ Potential for spin-based information processing in a thin-film molecular semiconductor. _Nature_

503, 504–508 (2013). https://doi.org/10.1038/nature12597 Download citation * Received: 06 April 2013 * Accepted: 21 August 2013 * Published: 27 October 2013 * Issue Date: 28 November 2013 *

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