BEGIN:VCALENDAR VERSION:2.0 PRODID:IEEE vTools.Events//EN CALSCALE:GREGORIAN BEGIN:VTIMEZONE TZID:US/Mountain BEGIN:DAYLIGHT DTSTART:20190310T030000 TZOFFSETFROM:-0700 TZOFFSETTO:-0600 RRULE:FREQ=YEARLY;BYDAY=2SU;BYMONTH=3 TZNAME:MDT END:DAYLIGHT BEGIN:STANDARD DTSTART:20191103T010000 TZOFFSETFROM:-0600 TZOFFSETTO:-0700 RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=11 TZNAME:MST END:STANDARD END:VTIMEZONE BEGIN:VEVENT DTSTAMP:20191231T061116Z UID:F8C71D26-EDAE-463A-B622-763C5B033917 DTSTART;TZID=US/Mountain:20190510T110000 DTEND;TZID=US/Mountain:20190510T121500 DESCRIPTION:Mutually synchronized spin torque nano-oscillators (STNOs) are one of the promising platforms for bioinspired computing and microwave sig nal generation [1\,2]. Using STNOs one can achieve 90% recognition rate in spoken vowels [3]. However\, in order to do more complex tasks\, larger s cale synchronized oscillators are needed\, something that is not easily do ne with the STNOs demonstrated so far.\n\nIn my talk\, I will describe a d ifferent type of spin current driven device called spin Hall nano-oscillat ors (SHNOs)\, which can generate microwave frequencies over a very wide fr equency range [4]. The SHNOs are based on 50 – 120 nm wide nano-constric tions in Pt(5)/Hf(0.5)/NiFe(3) trilayers (all numbers in nm). When multipl e nano-constrictions are fabricated close to each other (300 – 1200 nm s eparation) they can mutually synchronize and chains of up to nine nano-con strictions have been demonstrated to exhibit complete synchronization [5]. For the first time\, we can now also synchronize two-dimensional SHNO arr ays with as many as 8 x 8 = 64 SHNOs [6]. The mutual synchronization is ob served both electrically and using scanning micro-BLS microscopy. Both the output power and linewidth of the microwave signal improves substantially with increasing number of mutually synchronized SHNOs\, such that quality factors of about 170\,000 can be reached. Following the approach of Romer a et al [3]\, we also demonstrate neuromorphic computing using a 4 x 4 SHN O array with two injected microwave signals as inputs. Given their high op erating frequency (~10 GHz)\, easy of fabrication\, and highly robust sync hronization properties\, nano-constriction SHNO arrays are likely the most promising candidates for neuromorphic computing based on oscillator netwo rks.\n\n[1] J. Grollier\, D. Querlioz\, and M. D. Stiles\, Proc. IEEE 104\ , 2024 (2016)\n\n[2] J. Torrejon et al\, Nature 547\, 428 (2017)\n\n[3] M. Romera et al\, Nature 563\, 230–234 (2018)\n\n[4] T. Chen\, R. K. Dumas \, A. Eklund\, P. K. Muduli\, A. Houshang\, A. A. Awad\, P. Dürrenfeld\, B. G. Malm\, A. Rusu\, and J. Åkerman\, Proc. IEEE 104\, 1919 (2016)\n\n [5] A. A. Awad\, P. Dürrenfeld\, A. Houshang\, M. Dvornik\, E. Iacocca\, R. K. Dumas\, and J. Åkerman\, Nature Physics 13\, 292–299 (2017)\n\n[6 ] M. Zahedinejad\, et al. arXiv:1812.09630 (2018)\n\nCo-sponsored by: UCCS \n\nSpeaker(s): Johan Åkerman\, \n\nRoom: A204\, Bldg: Osborne\, 1420 Aus tin Bluffs Park\, Colorado Springs\, Colorado\, United States\, 80918 LOCATION:Room: A204\, Bldg: Osborne\, 1420 Austin Bluffs Park\, Colorado Sp rings\, Colorado\, United States\, 80918 ORGANIZER:zcelinsk@uccs.edu SEQUENCE:0 SUMMARY:Two-dimensional mutually synchronized spin Hall nano-oscillator arr ays for highly coherent microwave signal generation and neuromorphic compu ting. URL;VALUE=URI:https://events.vtools.ieee.org/m/216643 X-ALT-DESC:Description: <br /><p>Mutually synchronized spin torque nano-osc illators (STNOs) are one of the promising platforms for bioinspired comput ing and microwave signal generation [1\,2]. Using STNOs one can achieve 90 % recognition rate in spoken vowels [3]. However\, in order to do more com plex tasks\, larger scale synchronized oscillators are needed\, something that is not easily done with the STNOs demonstrated so far.</p>\n<p>&nbsp\ ;</p>\n<p>In my talk\, I will describe a different type of spin current dr iven device called spin Hall nano-oscillators (SHNOs)\, which can generate microwave frequencies over a very wide frequency range [4]. The SHNOs are based on 50 &ndash\; 120 nm wide nano-constrictions in Pt(5)/Hf(0.5)/NiFe (3) trilayers (all numbers in nm).&nbsp\; When multiple nano-constrictions are fabricated close to each other (300 &ndash\; 1200 nm separation) they can mutually synchronize and chains of up to nine nano-constrictions have been demonstrated to exhibit complete synchronization [5]. For the first time\, we can now also synchronize two-dimensional SHNO arrays with as man y as 8 x 8 = 64 SHNOs [6]. The mutual synchronization is observed both ele ctrically and using scanning micro-BLS microscopy. Both the output power a nd linewidth of the microwave signal improves substantially with increasin g number of mutually synchronized SHNOs\, such that quality factors of abo ut 170\,000 can be reached. Following the approach of Romera et al [3]\, w e also demonstrate neuromorphic computing using a 4 x 4 SHNO array with tw o injected microwave signals as inputs. Given their high operating frequen cy (~10 GHz)\, easy of fabrication\, and highly robust synchronization pro perties\, nano-constriction SHNO arrays are likely the most promising cand idates for neuromorphic computing based on oscillator networks.</p>\n<p>&n bsp\;</p>\n<p>[1] &nbsp\; J. Grollier\, D. Querlioz\, and M. D. Stiles\, P roc. IEEE <strong>104</strong>\, 2024 (2016)</p>\n<p>[2] &nbsp\; J. Torrej on et al\, Nature <strong>547</strong>\, 428 (2017)</p>\n<p>[3] &nbsp\; M. Romera et al\, Nature <strong>563</strong>\, 230&ndash\;234 (2018)</p>\n< p>[4] &nbsp\; T. Chen\, R. K. Dumas\, A. Eklund\, P. K. Muduli\, A. Housha ng\, A. A. Awad\, P. Dürrenfeld\, B. G. Malm\, A. Rusu\, and J. &Aring\; kerman\, Proc. IEEE <strong>104</strong>\, 1919 (2016)</p>\n<p>[5] &nbsp\; A. A. Awad\, P. D&uuml\;rrenfeld\, A. Houshang\, M. Dvornik\, E. Iacocca\ , R. K. Dumas\, and J. &Aring\;kerman\, Nature Physics <strong>13</strong> \, 292&ndash\;299&nbsp\; (2017)</p>\n<p>[6] &nbsp\; M. Zahedinejad\, et al . arXiv:1812.09630 (2018)</p> END:VEVENT END:VCALENDAR