Lecture of Suderow at Cytef 2012
Transcription
Lecture of Suderow at Cytef 2012
LABORATORIO DE BAJAS TEMPERATURAS: CERCA DEL CERO ABSOLUTO Hermann Suderow Laboratorio de Bajas Temperaturas Departamento de Física de la Materia Condensada Instituto de Ciencia de Materiales Nicolás Cabrera Universidad Autónoma de Madrid (UAM) LABORATORIO DE BAJAS TEMPERATURAS: CERCA DEL CERO ABSOLUTO Historia y tecnología del helio liquido Puntos fríos en el mK : 3He – 4He Superconductividad Microscopía de la superconductividad Lord Rayleigh at the Royal Institution 1908. Helio líquido 1911. Superconductividad en Hg Kamerlingh Onnes Van der Waals "Helium is no longer a rare element" "While it was going on," Cady said, "we decided to take advantage of [Sir James] Dewar's recently published discovery that coconut charcoal would adsorb all gases [in the atmosphere] except helium, hydrogen, and neon very completely at the temperature of boiling liquid air" (-310 F). After making some coconut charcoal and building a glass apparatus to handle the gases, Cady and McFarland proceeded to immerse glass bulbs of the Dexter gas in liquid air and allowed them to stand for some time. … On Dec. 7, 1905, Cady and McFarland found that "instantly the yellow of the helium flashed up and the spectroscope showed all the lines of helium." The dominant spectroscopic line was identical to that found almost 40 years earlier in the spectroscopic analysis of the Sun that led to the extraterrestrial discovery of helium. The total amount of helium present in the Dexter gas was an astonishing 1.84%. Less than a month later, on January 1, 1906, E.H.S. Bailey, the chemistry department chair at Kansas, read a paper by Cady and McFarland describing their remarkable discovery before an ACS national meeting in New Orleans. …"assures the fact that helium is no longer a rare element, but a common element, existing in goodly quantity for uses that are yet to be found for it." Heike Kamerlingh‐Onnes y su ayudante Mr.Flim 2008 – centenario IIR 1908 – centenario primera licuación del helio Kamerlingh Onnes • • • • Primera cátedra en Física experimental en Holanda Licuación de aire en 1892 Licuación de hídrógeno en 1906 10 de Julio de 1908: Licuación de helio 1908 en la ceremonia de inauguración del International Congress of Refrigeration, H. Kamerlingh Onnes propone: “The creation of an international organization of refrigeration which would further the work of the congress” He insisted that one of the commissions be devoted to scientific problems. Dewar Sir J. Dewar R. Burger Dewar modernos para helio líquido Helio Vacío Nitrógeno Vacío H. Kamerlingh Onnes y la Física española Kamerlingh Onnes, H. and J. Palacios Martinez, Vapor pressure of hydrogen and new determinations in the liquid hydrogen region (in Spanish) Anales de la Real Sociedad Española de Fisica y Quimica., 1922. 20: p. 233-42 Blas Cabrera J. Palacios Martínez Nicolás Cabrera DESARROLLO DE CRIOGENIA The SEGAINVEX team (headed by M. Pazos) Durante 10 años, H. Kammerlingh-Onnes trabajó con solo 60 cm3 de helio líquido En la UAM, hoy se licuan 30 000 000 cm3 de helio líquido cada año LBTUAM works for industry (e.g. EADS) LBTUAM belongs to REDLAB (lab nr 287) http://www.madrimasd.org/Laboratorios/default.asp Técnicas de enfriamiento • Evaporación 4He 3He 1K 250 mK • Dilución de 3He en 4He 5 mK • Desimanación adiabática < 1 mK • Pomeranchuk << 1 mK LABORATORIO DE BAJAS TEMPERATURAS: CERCA DEL CERO ABSOLUTO Historia y tecnología del helio liquido Puntos fríos en el mK : 3He – 4He Superconductividad Microscopía de la superconductividad 4He 3He 3He 4He Cooling technique Fase concentrada 3He in 4He Fase diluida H TS T S 3 He diluido S 3 He S T , x Cómo forzar el paso de 3He del concentrado al diluido ? 2 2 R T TF x From A.T.M. de Waele Dilución de 3He en 4He : 1962 H. London 1951 F. London Dilución de 3He en 4He : 1962 Fase concentrada Fase diluida Cómo forzar el paso de 3He del concentrado al diluido ? PCM R PE TCM xDCM TE xDE V4 Equilibrio: PCM PE 0 Con 6.4% 3He en 4He Cámara de mezcla 1% 3He en 4He Evaporador TCM 0.01K TE 0.7 K Cómo forzar la dilución de 3He concentrado en 3He diluido ? PCM R PE TCM xDCM TE xDE V4 Bombeando: PCM PE 1.6kPa 6.4% 3He en 4He Cámara de mezcla 0% 3He en 4He Columna de 70 cm de 4He: Evaporador 1kPa Dilución - Evaporación Fase concentrada T2 Potencia enfriamiento (W) Fase diluida 800 exp (-1/T) Evaporación 3 He Dilución 600 MX400 400 200 K25 0 0.0 0.2 Temperatura 0.4 El criostato de dilución Cryogenic vaccum T pV p0 T0 Cp / R e L0 1 1 R T0 T Vacío casi perfecto en el mK Criogenia de dilución NO HELIUM BATH PULSE TUBE Entorno limpio, estable, fiable, versátil ESA PLANCK Criogenia de dilución en el LBTUAM - 100 mK + 10 T (2001) SEGAINVEX - 7 mK + 9 T - 7 mK + 9 T - 100 mK + 5 T + 1 T + 1 T Por qué el milikelvin ? “While the number of scientists interested in the thermodynamics of acheiving low temperatures is decreasing, many more are interested in using these refrigerators to perform experiments in the mK range.” Innovating for nanotechnology applications Our recent change of company name, from Superconductivity to NanoScience, is a recognition of our increasingly important role in providing sample environments that enable world-leading research in nanotechnology. Of course this encompasses many areas of research that have evolved as important fields, within the broad scope of nanotechnology, and we have pioneered many of the solutions which are now key tools in this area. Notable amongst these are our optical spectroscopy cryogenic systems and our ultra low temperature platforms. In particular we are celebrating the 40th anniversary of the development of the dilution refrigerator this year, a product range that continues to benefit from our innovative approach. La “criofobia” Sevilla 2008 LBTUAM Programas de investigación europeos, nacionales y regionales Colaboración con grupos teóricos Acceso a grandes instalaciones Dos puntos fríos a 7mK con 0.4mW de capacidad de enfriamiento a 100mK Una de las mayores capacidades de enfriamiento que se pueden obtener con la tecnología actual. First cool down Temperature (K) 100 10 1 0.1 Present base temperature : 8 mK 0.01 0 1 2 3 4 5 6 Time (hours) 7 8 9 http://www.uam.es/citecnomik http://www.uam.es/inc T 300 K 10 K 7 mK H 17 T P 500 kbar Transporte y magnetismo Microscopía a escala atómica Termodinámica [email protected] Working for industry Herschel y Planck ESA http://www.uam.es/inc • Ofertar formación en las tecnologías que se utilizan en los laboratorios del INC. • Poner en contacto a investigadores en Ciencia de Materiales reconocidos internacionalmente, con tecnólogos de otros laboratorios, instituciones y empresas. • Desarrollar una escuela de instrumentación avanzada para el negocio de la Ciencia. http://www.uam.es/citecnomik http://www.uam.es/inc T 300 K 10 K 7 mK H 17 T P 500 kbar Transporte y magnetismo Microscopía a escala atómica Termodinámica [email protected] LABORATORIO DE BAJAS TEMPERATURAS: CERCA DEL CERO ABSOLUTO Historia y tecnología del helio liquido Puntos fríos en el mK : 3He – 4He Superconductividad Microscopía de la superconductividad AN INTERESTING MACROSCOPIC QUANTUM PHENOMENON Heike Kamerlingh-Onnes, 1911 Applications of superconductivity 1. Zero resistance 2. Quantum coherence 1. Industry (e.g. energy) 2. Instrumentation (e.g. SQUID) metrology 3. “Big Science” Efecto del campo magnético. Anillo superconductor (R=0, M=‐B) By 1914 Onnes established a permanent current, or what he called a “persistent supercurrent,” in a superconducting coil of lead. The coil was placed in a cryostat at low temperature, with the current being induced by an external magnetic field. With no resistance, the electrons in the coil were free to continue to flow indefinitely. After seeing the current, Austrian-Dutch physicist Paul Ehrenfest wrote to Nobel physicist Hendrik Lorentz in the Netherlands, “It is uncanny to see the influence of these ‘permanent’ currents on a magnetic needle. You can feel almost tangibly how the ring of electrons in the wire turns around, around, around—slowly, and without friction.” Onnes Weiss Einstein Ehrenfest Langevin 1932 : Demostración de la superconductividad en la Royal Institution Superconductores de tipo I y de tipo II Shubnikov y Abrikosov Tipo I - efecto Meissner, diamagnetismo perfecto H Tipo I H HC N HC = 100 - 1000 G S 0 TC H HC2 T Tipo II H N HC HC1 < 100 G HC2 = 104 - 105 G HC1 Tipo II - estado mixto, vórtices S 0 TC T Applications of superconductivity Applications of superconductors : “Big Science” La superconductividad : transformando la red eléctrica ? Smart grid Tecnología superconductora: Generación, almacenamiento, distribución, conversión, usuario final Estrategia ?? Nuevos materiales Técnicas criogénicas Aplicaciones de la superconductividad Pulse tube “Evercool” Plantas de licuación helio Nanoscopic cooling Campo magnético Corriente Presión Superconductores de tipo I y de tipo II Shubnikov y Abrikosov Tipo I - efecto Meissner, diamagnetismo perfecto H Tipo I H HC N HC = 100 - 1000 G S 0 TC H HC2 T Tipo II H N HC HC1 < 100 G HC2 = 104 - 105 G HC1 Tipo II - estado mixto, vórtices S 0 MICROSCOPIA DE VÓRTICES TC T Microscopic theory J.Bardeen, L. Cooper, J. Schrieffer (BCS, 1957) Superconductor e i Cooper pairs S=0 L=0 k , k , 2 Ek , (k ) 2 k N (E) E E 2 2 BCS 1.76k BTc superconductores Sonido producido solo por el motor Sonido producido por el avión Electron tunneling I (V , z ) VN ( E F )e 1.025 nA - pA z Low temperature spectroscopy 87 eV = 1 K N (E) k , k , E 3 =1mV T=0.3 K T=1 K 2 1 0-4 -3 -2 -1 0 1 2 Bias voltage (eV/0) E 2 Normalized tunnelling conductance dI f ( E eV ) N (E) dE dV V 4 2 e i 2 Ek k2 , (k ) N ( E ; x, y ) 3 4 Microscopy of the superconducting gap in type II materials H Mixed state Hc2 Normal phase Mixed state H Meissner state Hc Hc1 Meissner state Tc T H d(nm) 50 / H(T) 2 Ψ ns d H J r J e i k , k , N (E) E E 2 2 0 H c2 2 2 Microscopy Optical, SEM, SPM SPM at cryogenic temperatures Cryogenic operation of a scanning probe microscope eliminates Brownian motion altogether, provides for resolution in energy and enables macroscopic quantum behavior Atomic scale manipulation with cryogenic scanning probe microscopy T=4.2 K D. Eigler, IBM Cryogenic scanning probe microscopy eliminates Brownian motion altogether and enables macroscopic quantum behavior 50 LABORATORIO DE BAJAS TEMPERATURAS: CERCA DEL CERO ABSOLUTO Historia y tecnología del helio liquido Puntos fríos en el mK : 3He – 4He Superconductividad Microscopía de la superconductividad The vortex lattice through STM Measure far below Tc (here 7 K), high mechanical stability of tip-sample Cryogenic scanning probe microscopy eliminates Brownian motion altogether, provides for resolution in energy and enables macroscopic quantum behavior pA Efficient microscopy of superconducting vortices pm stability mK temperatures 100 mK is the target Microscope design Cooling and environment Principle of operation of a scanning tunneling microscope Fine positioning piezoelectrics + Coarse motor Z nm x, y 20 V Scanning window in the m range with sub atomic resolution z y x Position without heating with nm resolution Y X Designing a cryogenic scanning tunneling microscope Stiffness fvibration isolation Stiff and light Soft and heavy fmicroscope Tip-sample motion shall be in phase 1 f0 2 k meff Dilution refrigerators of the LBTUAM Mezclas de 3He y 4He 5 meter long flexible pumping line 4He 5 meter long flexible pumping line 3He rotary pump L N Classical Oxford Instruments dilution refrigeration technology Development: Support Pumping Liquid consumption Sample holders Gas handling system 3He‐4He mixture reservoirs Separate building rotary pump STM holder for dilution refrigeration Mezclas de 3He y 4He STM head is posed on fiber glass loom Specific precision motion system using a series of ropes with a room temperature actuator without measurable heating at 100 mK STM/S head for dilution refrigeration MADRID LBTUAM - 100 mK + 9 T - 300 mK + 13 T - 10 mK + 9 T (current flow) - 100 mK + 3D VECTOR MAGNET In situ tip and sample preparation methods 2 m STM electronics at LBTUAM Mezclas de 3He y 4He Switchable filter’ Motor Z’ PA243 I-V converter Tunnel current RF filters 6x PA243 RF filters Bias voltage RF filters Industrial PC DAC ADC OP27 RF filters Power supply +/- 15 V RF filters … 6 PIEZO SCANNING DRIVES Power supply +/- 15 V +/- 140 V Power supply Resolution in spectroscopy of <15 eV (<150 mK) Home made equipment: design, construct, test SEGAINVEX 100 mK 100 mK + 3D (5 T + 1 T + 1 T) AUTOMATIZED 3D VECTOR MAGNET Cryogenic scanning probe microscopy eliminates Brownian motion altogether, provides for resolution in energy and enables macroscopic quantum behavior pA Efficient microscopy of superconducting vortices pm stability ten eV resolution 100 mK is the target Microscope design Cooling and environment Results 0.35 nm 1.25 nm 0.29 nm Atomic scale imaging at 100 mK c a Se Nb b 1/CDW 1/a 2H‐NbSe2 1.7nm 2H‐NbS2 CDW 3a 1% Direct observation of thermally induced vortex depinning Temperature between (0.1K‐2.1K) 144 images 8 min each one Several images at each T Physics Today, see youtube channel physics update http://www.youtube.com/watch?v=7fgNpqgZWKY http://www.youtube.com/user/citecnomik1 Vortex bundles with weak pinning at 100 mK Increasing the field in steps No time variation of flux distribution Pinning produces spatial variation of B Critical state Campo Crítico Hc2 (T) FL=‐FP 6 5 4 3 2 1 0 0 1 2 3 Temperatura (K) 33 STS images 0.04 T steps 4 FL J B d Vortex pinning 2 Ψ ns I H J r J FL FP J c B RI/V Itunnel VI/V=108·Itunn Pinning centers • surface corrugation (L) •… Vbias + - ~ nA Tip + SC sample > mA R Isamp le el I/V converter Vbias + Vsample + - Microscopic determination of the critical current J = 0.8·105A/m2; H = 0.5T J (A/m2) T= 4K J0 = 1.2·105 A/m2 0.8·105A/m2 T= 5K J = 0.4·105A/m2; H = 0.5T 0.4·105A/m2 0A/m2 0.5T H (T) H0 = 4.1T T = 4K T = 5K T = 6K J = 0A/m2; H = 0.5T T0 = 7.2K T (K) Tunnel current I (VBias) Bias VBias d T = 4K In plane current Isample Vortex motion In plane current T = 5K T = 6K LABORATORIO DE BAJAS TEMPERATURAS: CERCA DEL CERO ABSOLUTO Tecnología del liquido Puntos fríos en el mK Superconductividad Microscopía de la superconductividad Future work : cryofree high magnetic fields Future of cryogenic scanning probe microscopy Compact design enabling Versatility (cryocooler) Extreme conditions: high magnetic fields and lower temperatures Temperature in K Spatial resolution in pm LHe 10 LHe 10000 1000 1 100 Cryocooler 10 1 Superconducting solenoid Cryocooler 0.01 0.1 Resistive high field magnet Superconducting solenoid 0.1 UHV + LHe Resistive high field magnet UHV + LHe Future of cryogenic scanning probe microscopy Compact design enabling Versatility (cryocooler) Extreme conditions: high magnetic fields and lower temperatures High magnetic fields are one of the most powerful tools available to scientists for the study, the modification and the control of the state of matter. Europe should have a dedicated world class magnet field laboratory (EMFL) which provides the highest possible fields (both continuous and pulsed) to its researchers Campus CEI 15 solenoides superconductores de > 8 T Campo magnético de 17 T Desarrollo y construcción de solenoides de 3 ejes UAM + CSIC + … Cryogenic scanning probe microscopy A. Maldonado, J.A. Galvis Echeverry, M.R. Osorio, R.F. Luccas, P. Kulkarni, V. Crespo A. Buendía, I. Guillamón, J.G. Rodrigo, S. Vieira Laboratorio de Bajas Temperaturas Dpto. Física de la Materia Condensada Instituto de Ciencia de Materiales Nicolás Cabrera Universidad Autónoma de Madrid (UAM) J. Sesé, R. Córdoba, A. Fernández Pacheco, J.M. de Teresa, R. Ibarra ICMA, Unizar, Instituto de Nanociencia de Aragón F. Guinea Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas, Madrid S. Bud’ko, P.C. Canfield Ames Laboratory, Ames – USA S. Bannerjee IIT Kanpur – India V. Tissen, Chernogolovka, Russia T. Baturina, Novosibirsk, Russia, V. Vinokur, Argonne, USA L. Cario, Nantes; P. Rodiere, P. Lejay, J.P. Brison, Dai Aoki, J. Flouquet Institut Néel and SPSMS/DRFMC E. Navarro Moratalla, C. Martí Gastaldo, E. Coronado, ICMol Valencia Experimentos LBTUAM de demostración DIFUSIÓN http://www.youtube.com/user/citecnomik1/ Gracias por su atención http://www.uam.es/citecnomik http://www.uam.es/inc