Justin's Labnotes

SQUID - high pressure I

2011-02-25T15:55:00.000-08:00

We just got a set of easyLab system from our beloved collaborators in UNLV, which is designed for the Quantum Design SQUID. Here is the product information. (http://www.easylab.co.uk/productsdetails.asp?ID=12&iflgGreenSet=1)

Top left picture shows the high-pressure cell (Mcell 10) attached on the SQUID sample probe, and the top right picture shows the "Mpress" and pressure reader.

I have to say that, when cooling down the pressure cell in the SQUID, the cell keeps loosing from the top screw, and eventually falls off from the probe, even I use Mpress to tight it up to 50 N. Hence, the sample longitudinal scan is changing with time. Maybe I haven't find the trick to avoid it.

SQUID - ambient measurement.

2011-02-25T15:04:00.001-08:00

Here is the traditional Quantum Design MPMS XL in our lab at the Glenn T. Seaborg Center at Lawrence Berkeley National Laboratory.

I have some experience on measuring small crystals loaded in a straw with two blocks of "quartz wall" (ambient pressure).

Since the magnetic correction is small for the "quartz wall", for most "magnetic" samples, the voltage vs. longitudinal length scan looks just like the diagrams shown in the users' manual.

However, to play the same measurement under high-pressure is not so easy, since we are going to use a "giant" pressure cell, which is composed of a few parts, and contributes a significant magnetic background to the data (1st order), the slow thermal reaction of the pressure cell maybe another problem that affects precision (2nd order).

Beamline schedule (06/16/09 - 06/22/09)

2009-06-05T12:09:00.000-07:00

Beamline schedule (06/16/09 - 06/22/09)
Beamline 11-2 # 1-650-926-8650
(Please note the new location and phone number of this beam run!)

06/16 (Tuesday)
am Bud / Justin / Scott (setup)

06/17 (Wednesday)
9:30 am - 6:00 pm Bud
5:30 pm - 1:00 am Mike / Carley
0:30 am - 9:00 am Justin

06/18 (Thursday)
9:30 am - 6:00 pm Bud / Carley
5:30 pm - 1:00 am Scott / Ben
0:30 am - 9:00 am Justin

06/19 (Friday)
9:30 am - 6:00 pm Bud
5:30 pm - 1:00 am Scott / Ben
0:30 am - 9:00 am Mike

06/20 (Saturday)
9:30 am - 6:00 pm Bud
5:30 pm - 1:00 am Justin
0:30 am - 9:00 am Scott

06/21 (Sunday)
9:30 am - 6:00 pm Bud
5:30 pm - 1:00 am Mike
0:30 am - 9:00 am Scott

06/22 (Monday)
6:30 am (Breakdown) Scott & Justin

Beamline 10-2 Schedule (Apr 2 - 10, 2009)

2009-03-18T15:34:00.000-07:00

Beamline schedule (04/02/09 - 04/10/09)
Beamline 10-2 # 1-650-926-5102

04/02 (Thursday)
10:00 am - 6:00 pm Bud / Justin / Ben (setup)
5:30 pm - 1:00 am Justin
00:30 am - 9:00 am Scott

04/03 (Friday)
9:30 am - 6:00 pm Bud / Ben / Carley ?
5:30 pm - 1:00 am Mike
0:30 am - 9:00 am Scott

04/04 (Saturday)
9:30 am - 6:00 pm Bud / Justin / Carley ?
5:30 pm - 1:00 am Mike
0:30 am - 9:00 am Scott

04/05 (Sunday)
9:30 am - 6:00 pm Bud
5:30 pm - 1:00 am Scott
0:30 am - 9:00 am Justin

04/06 (Monday)
up to 9:00 am Justin (Machine Physics)

04/07 (Tuesday)
Machine Physics

04/08 (Wednesday)
10:00 am - 6:00 pm Bud (setup)
5:30 pm - 1:00 am Mike
0:30 am - 9:00 am Justin

04/09 (Thursday)
9:30 am - 6:00 pm Bud
5:30 pm - 1:00 am Mike
0:30 am - 9:00 am Justin

04/10 (Friday)
6:30 am (Breakdown) Justin & Scott

Notes on the LaCoO3 film samples.

2008-11-07T12:47:00.000-08:00

LaCoO3 film samples were grown on STO or Nb:STO.

1) Need to take fluorescence EXAFS data using polarized X-ray.
X-ray's polarization is on horizontal axis.
Glancing angle for c-axis; almost right angle for a-axis(here a .eq. b).

2) On taking Co K-edge data, we have to take care of the fluorescence of Ti(~ 4 keV).
Need to adjust number of thin Al foils to reduce Ti effect.

Beamline 10-2 Schedule (Nov 21 - Nov 25, 2008)

2008-11-07T12:10:00.000-08:00

Beamline schedule (11/21/08 - 11/25/08)
Beamline 10-2 # 1-650-926-5102

11/21 (Friday)
9:30 am - 6:00 pm Bud / Chris (setup)
5:30 pm - 1:00 am Scott
12:30 am - 9:00 am Justin

11/22 (Saturday)
9:30 am - 6:00 pm Bud / Mike
5:30 pm - 1:00 am Scott
12:30 am - 9:00 am Justin

11/23 (Sunday)
9:30 am - 6:00 pm Bud / Carley
5:30 pm - 1:00 am Scott
12:30 am - 9:00 am Justin

11/24 (Monday)
9:30 am - 6:00 pm Bud
5:30 pm - 1:00 am Mike
12:30 am - 9:00 am Justin

11/25 (Tuesday)
7:30 am (Breakdown) Justin & Scott

Superconductivity Samples' Experiment Information

2008-04-09T10:09:00.000-07:00

CeFe4As12
Ce L3 - 10 @ 5724 eV
Fe K - 15 @ 7112 eV

Pr(Os0.9Ru0.1)4Sb12
Pr L3 - 11 @ 5964 eV
(Japan)

Pr(Os0.9Ru0.1)4Sb12
Pr L3 - 11 @ 5964 eV
(UC San Diego)

ZnS:Cu,Cl sample list

2008-04-09T10:03:00.000-07:00

GGS22 BLUE/GREEN STANDARD
GGL21 BLUE/GREEN LONG LIFE
GGS42 GREEN STANDARD
GGL11 ORANGE LONG LIFE

Beamline 10-2 Schedule (Apr 9 - Apr 16, 2008)

2008-03-13T15:10:00.000-07:00

Beamline schedule (04/09/08 - 04/16/08)
Beamline 10-2 # 1-650-926-5102

04/08 (Tuesday)
Justin delivery some of the boxes to SSRL

04/09 (Wednesday)
9:30 am - 6:00 pm Bud / Chris (setup)
5:30 pm - 1:00 am Lisa
12:30 am - 9:00 am Justin

04/10 (Thursday)
9:30 am - 6:00 pm Bud / Chris / Carley
5:30 pm - 1:00 am Lisa / John
12:30 am - 9:00 am Justin

04/11 (Friday)
9:30 am - 6:00 pm Bud
5:30 pm - 1:00 am John / Robert
12:30 am - 9:00 am Justin

04/12 (Saturday)
9:30 am - 6:00 pm Bud
5:30 pm - 1:00 am Chris
12:30 am - 9:00 am Justin

04/13 (Sunday)
9:30 am - 6:00 pm Bud ? / Carley / John
5:30 pm - 1:00 am Lisa
12:30 am - 9:00 am Chris

04/14 (Monday)
9:30 am - 6:00 pm Bud
5:30 pm - 1:00 am John / Robert
12:30 am - 9:00 am Chris

04/15 (Tuesday)
9:30 am - 6:00 pm Lisa (leave before 4:30)
5:30 pm - 1:00 am Bud (come in ~ 1 pm) / John / Carley
12:30 am - 9:00 am Justin

04/16 (Wednesday)
6:30 am - 8:00 pm Bud / Justin (Breakdown)

The edges we are looking at :
Ce L3 Nd L3 Pr L3
(CuS) Cu-K (ZnS:Cu, Mn, etc.) Cu, Zn, Mn-K
(LaOFeAs) Fe-K

For some of us, you may need these:
The Stanford Synchrotron Radiation Laboratory
2575 Sand Hill Road, Menlo Park, California, 94025, USA

http://www.vta.org/

http://www.scmtd.com/

Beamline 10-2 Schedule (Nov 14 - Nov 20)

2007-10-25T14:12:00.000-07:00

Beamline schedule (11/14/07 - 11/20/07)
Beamline 10-2 # 1-650-926-5102

11/14 (Wednesday)
8:30 am - 6:00 pm Bud / Jacob (setup)
5:00 pm - 1:00 am Bud
12:30 am - 9:00 am Justin

11/15 (Thursday)
8:30 am - 6:00 pm Bud / Carley / Anna
5:00 pm - 1:00 am Lisa
12:30 am - 9:00 am Justin

11/16 (Friday)
8:30 am - 6:00 pm Bud / Robert
5:00 pm - 1:00 am Jacob / John
12:30 am - 9:00 am Justin

11/17 (Saturday)
8:30 am - 6:00 pm Lisa
5:00 pm - 1:00 am Justin
12:30 am - 9:00 am Jacob

11/18 (Sunday)
8:30 am - 6:00 pm Bud / John / Robert
5:00 pm - 1:00 am Justin
12:30 am - 9:00 am Jacob

11/19 (Monday)
8:30 am - 6:00 pm Bud
5:00 pm - 1:00 am Bud
12:30 am - 9:00 am Justin

11/20 (Tuesday)
8:30 am - 7:00 pm Bud / Justin (Breakdown)

To my "compatriots"---an email to some common questions

2007-07-21T21:55:00.000-07:00

My friends,

I am glad to receive emails regarding some application questions.

I have got some similar emails before, and I guess I will keep receiving them for the coming years. Therefore, I decide to publish my "answers" to those questions on the website, though they are only my narrow thoughts.

First, I am happy to choose UC Santa Cruz to continue my exploration on Physics, it's really a good small town for some one who loves ocean and forest. Plus, people are nice and warm-hearted here(most of the time), they won't lose patience to listen to my poor English.

Next, it's not too far to the Chinese civilization. 45 minutes driving distance to the nearest Chinese supermarkets, because it's close to the "Silicon Valley". The Asians' population at UCSC was said the lowest among UC system, but still very high, because it's CA.

In the Physics/Astronomy department at UCSC, there are some Chinese(7?), some are graduates while others are post-doc. The Physics Department recruits 10-15 graduate students each year. Depending on the bugdet, it will recruit 1-2 international students every year. I don't think we have any students without funding here. Normally, the first year students do TA, then depending on their choice, they may do RA or TA for the future years. I think it's a good practice to be a TA, because I can practice my English muscles.

In the Physics Department, we have several directions: High Energy and Cosmology, Experimental and Theoretical Condensed Matter. I am a condensed matter guy. I feel that every year, the population of new grads who are in favor of those research directions changes a lot. Therefore, I really can't say which direction has the best chance. I choose experimental condensed matter that year, just because I like it. If you like experimental condensed matter, we have several groups: one is doing neutron scattering, one is doing EXAFS, one is dong ARPES(these groups don't do experiments at UCSC, two of them do experiments at SSRL or LBNL, one at Argone or Los Almos, they do data analysis at school.); the other two labs are doing something like materials. If you get here, you can do one year rotation among any labs you are interested in.

Any way, if let me choose this year, I will still choose condensed matter.

If you have more questions, just send me a email.

By the way, I guess you just send emails to those whose names look like Chinese, however, some of them are domestic students, not international students, so they really know nothing about your questions.
Good luck!

So if you have further questions, I am happy to add more words on my website.

Beamline 10-2 Schedule (June 18 - June 25)

2007-06-12T12:47:00.000-07:00

Mon (6/18)
Bud / Jesse (setup 10am - 5pm)
Jacob (5pm - 1am)
Justin (1am - 9am)

Tue (6/19)
Bud (9am - 6pm)
Lisa (5pm - 1am)
Justin (1am - 9am)

Wed (6/20)
Bud (9am - 6pm)
Jesse (5pm - 1am)
Lisa (1am - 9am)

Thur (6/21)
Bud / Nalini / Dave (9am - 6pm)
Jacob (5pm - 1am)
Jesse (1am - 9am)

Fri (6/22)
Justin (9am - 6pm)
Nalini (5pm - 1am)
Jesse (1am - 9am)

Sat (6/23)
Bud (9am - 6pm)
Jacob (5pm - 1am)
Nalini (1am - 9am)

Sun (6/24)
Dave / Justin (9am - 6pm)
Lisa / Ingrid (5pm - 1am)
Nalini (1am - 9am)

Mon (6/25)
Nalini / Lisa / Justin (Breakdown @ 6 am)

Beamline 10-2 Schedule (May 16 - 21)

2007-05-09T12:35:00.000-07:00

Wed (5/16)
Bud / Justin (setup 10am - 5pm)
Bud / Jacob (5pm - 1am)
Lisa (1am - 9am)

Thur (5/17)
Geza (9am - 5:00pm)
Bud(3pm) / Jesse (5pm - 1am)
Justin (1am - 9am)

Fri (5/18)
Bud (9am - 5pm)
Geza (5pm - 1am)
Justin (1am - 9am)

Sat (5/19)
Lisa (9am - 5pm)
Jacob / Justin (5pm - 1:00am)
Jesse (1am - 9am)

Sun (5/20)
Bud (9am - 5pm)
Lisa (5pm - 1:00am)
Jesse (1am - 9am)

Mon (5/21)
Bud / Justin (Breakdown 6 am)

Adding new 22% data

2007-03-03T21:03:00.000-08:00

We can see the difference between the new mag31-22% data and the old 22% data. The step height of the new one is a little smaller that the old one. Which indicates that the new one is more like an "insulator" at low T.
The result is consistent with the change in the resistivity of the new 22% sample measured by J. J. Neumeier.

Little Dog

2007-02-22T23:05:00.000-08:00

LCMO data (x = 0.16-0.22)

2007-02-22T22:13:00.000-08:00

Data points for LCMO (x = 0.16 - 0.22)

2007-02-22T21:16:00.000-08:00

16%	18%	20%	22%
3	3	3	3
20	20	20	20
40	40	40	40
60	60	60	60
80	70	70	80
100	100	100	100
120	120	120	105
135	135	135	120
140	140	140	135
150	150	150	140
155	155	155	150
160	160	160	155
170	170	170	160
175	175	180	170
180	180	185	175
185	185	190	180
195	190	195	185
200	195	200	190
210	200	210	195
220	210	225	195
250	225	250	200
260	250	270	210
270	270	275	220
300	275	308	250
308	308	320	260
340	320	348	270
348	348	398	300
398	398	448	303
448	448	498	345
498	498	555	376
555	555		406
			435
			465
			495
			524
			555

Preliminary results by ananlyzing LCMO (16%-22%)

2007-01-24T16:03:00.000-08:00

This is the Sigma^2 vs T for different samples with doping level x = 16%,18%,20%,22%.

A sharp increase in Sigma^2 (Sigma is the width of the Mn-O pair distribution function "PDF")near Tc.

The magnitude of the step decreases rapidly with decreasing x.

The value of Sigma^2 at low T is close to the value for zero-point motion for x = 22%, but increases substantially for lower x, which indicates that in the magnetized state there is either a large Jahn-Teller distortions or a static distortion which remains at low T.

The end compound LaMnO3 has a large J-T distortion, so we think it's caused by J-T distortion.

Also the magnetization at low T is small for lower x, indicating that not all of the sample is ferromagnetic, regions of antiferromagnetism may remain.

Mn-O standard for LCMO low doping samples and LSCO

2006-11-20T13:20:00.001-08:00

I tried to use FEFF to calculate the Mn-O function from Norby's LaMnO3 and Poe*'s CaMnO3, and combine them with x = 0.2 to make a new standard, but failed. The XI and NX for them are different, so the computer can't just add them together. Tried with FEFF8.20 and FEFF6.

Then I tried to make the similar standard for Co-O, failed at the same problem.

Start the labnotes

2006-11-20T00:37:00.000-08:00

16%	18%	20%	22%
3	3	3	3
20	20	20	20
40	40	40	40
60	60	60	60
80	70	70	80
100	100	100	100
120	120	120	105
135	135	135	120
140	140	140	135
150	150	150	140
155	155	155	150
160	160	160	155
170	170	170	160
175	175	180	170
180	180	185	175
185	185	190	180
195	190	195	185
200	195	200	190
210	200	210	195
220	210	225	195
250	225	250	200
260	250	270	210
270	270	275	220
300	275	308	250
308	308	320	260
340	320	348	270
348	348	398	300
398	398	448	303
448	448	498	345
498	498	555	376
555	555		406
			435
			465
			495
			524
			555

16%	18%	20%	22%
3	3	3	3
20	20	20	20
40	40	40	40
60	60	60	60
80	70	70	80
100	100	100	100
120	120	120	105
135	135	135	120
140	140	140	135
150	150	150	140
155	155	155	150
160	160	160	155
170	170	170	160
175	175	180	170
180	180	185	175
185	185	190	180
195	190	195	185
200	195	200	190
210	200	210	195
220	210	225	195
250	225	250	200
260	250	270	210
270	270	275	220
300	275	308	250
308	308	320	260
340	320	348	270
348	348	398	300
398	398	448	303
448	448	498	345
498	498	555	376
555	555		406
			435
			465
			495
			524
			555

16%	18%	20%	22%
3	3	3	3
20	20	20	20
40	40	40	40
60	60	60	60
80	70	70	80
100	100	100	100
120	120	120	105
135	135	135	120
140	140	140	135
150	150	150	140
155	155	155	150
160	160	160	155
170	170	170	160
175	175	180	170
180	180	185	175
185	185	190	180
195	190	195	185
200	195	200	190
210	200	210	195
220	210	225	195
250	225	250	200
260	250	270	210
270	270	275	220
300	275	308	250
308	308	320	260
340	320	348	270
348	348	398	300
398	398	448	303
448	448	498	345
498	498	555	376
555	555		406
			435
			465
			495
			524
			555