Differences

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--- afm [2025/04/22 09:46] – [Step-by-step walk through for AC mode imaging] ethanminot
+++ afm [2025/05/01 19:33] (current) – ethanminot
@@ Line 10: / Line 10: @@
 ===== Scheduling time =====
-The AFM calendar is managed by [[https://relms.oregonstate.edu/facilities|RELMS]]. On the RELMS website, our lab is listed as "Quantum Materials Lab". RELMS is a university-wide system administered by a team of 3 OSU employees. If you have not registered with RELMS before, the RELMS team will help you sign up and associate your billing indexes with your account. You must be trained on the AFM before you can book time on the RELMS calendar.
+The AFM calendar is managed by [[https://relms.oregonstate.edu/facilities|RELMS]]. On the RELMS website, our lab is listed as "Quantum Materials Lab". RELMS is a university-wide system administered by a team of three OSU employees. If you have not registered with RELMS before, the RELMS team will help you sign up and associate your billing indexes with your account. You must be trained on the AFM before you can book time on the RELMS calendar.
 Basic rules about booking time:
   *People who have scheduled time get priority.
   *Don't block off an entire 9am-5pm workday - leave at least an hour for someone to do a quick characterization.
+Every time you use the AFM, follow these steps:
+  - Write your name and date in the physical logbook
+  - Open your RELMS booking on the computer (or your cell phone) and "start" the session.
+  - Use the AFM
+  - Open your RELMS booking on the computer (or your cell phone) and "end" the session. RELMS will then bill your index for the actual time you used the AFM.
+  - Complete your logbook entry in the physical logbook.
+If you forget to start and/or end the RELMS booking, you will get an email from RELMS asking you to enter the actual time that you used the AFM. Please follow the instructions in the email.
@@ Line 53: / Line 62: @@
 ===== Step-by-step walk through for AC mode imaging =====
+//If a tip change is needed - see the [[AFM tip change information]]//
   - Sign into the black notebook (on the table next to the AFM)
   - Start your RELMS reservation on the [[https://relms.oregonstate.edu/facilities|RELMS website]].
   - Turn on the laser - Key switch on the AFM computer
-  - Open version 19 of the AFM software (latest stable version as of April 2025).
+  - Open version 19 of the realtime AFM software (latest stable version as of April 2025).
   - Click the first option, "Template"
   - Once software loads, set AC mode in master panel
@@ Line 103: / Line 113: @@
   - Leave controller and PC running unless expecting a power outage
 ===== Imaging rules of thumb =====
-It is easiest to get a good image on a small scan area (~ 1 micron). Starting from the default settings you can fine tune the image and then start increasing the scan size. Good settings will minimize ringing and reduce shadows while keeping the scan rate reasonably fast.
+It is easiest to get a good image on a small scan area (~ 2 micron). Starting from the default settings you can fine tune the image and then start increasing the scan size. Good settings will minimize ringing and reduce shadows while keeping the scan rate reasonably fast.
 **Beginner settings**
-  *Scan size 1 micron
+  *Scan size 2 micron (look at a random small feature on a flat background to verify the sharpness of the tip)
   *Scan rate < 15 micron / s
   *Integral gain 10
-  *Free amplitude 1 V (~ 100 nm)
+  *Free amplitude 1 V (corresponds to a cantilever motion of ~ 100 nm)
-  *Set point amplitude 0.65 V
+  *Set-point amplitude 0.75 V
+Sometimes the image is improved by lowering the set-point amplitude a few clicks. For example, this might fix parachuting.
+Sometimes the image is improved by withdrawing and re-running the autotune procedure (the resonant frequency might have changed).
-**Rule of thumb: "One high quality slow scan is worth ~5 low quality fast scans."**
+When you withdraw from the surface, check the free air amplitude is the same as you when you first tuned the tip.
-It is tempting to be impatient and try to 'tune' the imaging parameters to get the data you want from a 2 - 5 minute scan. This strategy often backfires though, if you need to return to old AFM images and find they are junk aside from the information you 'tuned' the parameters for. Also, 'tuning' these parameters in the first place probably takes ~10 minutes so you're not really saving time anyway. The best fix for many imaging problems is simply to lower the 'rate'. The price you pay is scan time. However, I've found that you actually save time (and headache) by taking a single high quality slow scan rather than a bunch of quick ones with little parameter adjustments in between. I find that adjusting the rate so that the scan speed is <10 micron/sec works well in nearly all cases.
+Another thing to try is a slower scan rate. The price you pay is scan time. However, I've found that you actually save time (and headache) by taking a single high quality slow scan rather than a bunch of quick ones with little parameter adjustments in between. I find that adjusting the rate so that the scan speed is <10 micron/sec works well in nearly all cases.
 **Using nanotubes as a diagnostic tool**